“Is SiF4 polar or nonpolar” is the main descriptive topic in this article. This article would represent the chemistry behind considering the polarity of SiF4. Lewis dot structure of the compound would be relevantly presented in this article as well.
There is a huge contrary explanation about the fact regarding polar non-polar nature of SiF4, Silicon tetrafluoride. The shape and the bond structure of the compound give reasonable approaches to provide proper consideration about the polarity of SiF4.
Is SiF4 polar or nonpolar?
SiF4 is non-polar. The compound occurs as great example of non-polar compound, which is quite attainable for showing the exceptional compound in the series of the polar compounds.
Silicon tetrafuloride has polar bonds between Silicon and fluorine but the tetrahedral shape eliminates the dipole movement of four Si-F sigma bonds. Otherwise, the dipole nature of the bonds is very strong.
Why is SiF4 nonpolar?
There is a huge reason, which generates complete non-polar nature among Silicon tetrafluoride. That reason is considered as the strong fact for SiF4 to possess zero dipole moment even after having polar bonds.
The high polarity between the bonds made by Silicon and Fluorine can be a great reason for considering the compound as a polar compound. However, the arrangement of the bonds is the reason, which creates a barrier in front of SiF4 for being polar compound.
The arrangement of bonds in the compound is symmetric with even number of bonds. As for being polar the arrangement of bonds in a compound is needed to be asymmetric with would provide huge dipole moment to the compound.
Due to symmetric bond arrangements around the central molecule the dipole moments are cancelled out by the pulling in opposite directions. In SiF4, action takes place, which is obvious in giving non-polar structure to the compound.
The asymmetric distribution of bonds is not able to creates the balance through the pulling effect from each of the atoms at the end of the bonds. Therefore, a certain amount of dipole moment is noticed to take place in the asymmetric compounds. And it makes the compound absolute polar compound.
Silicon tetrafluoride is recognised as a compound which creates “polarised Si delta plus and F delta minus.” Therefore, the bonds could be polarised bonds but the dipole moments are eliminated by the bond arrangements.
Octahedral molecular structure of SiF4 is represents that the polarisation takes place inside the bonds. However, the Lewis dot structure expresses the covalent bonding between the elements.
Silicon shares its two electrons from last cell with each of the four Fluorine atom and the fluorine atoms also share two electrons with Silicon. This mutual sharing crates the covalent bonding in between the Silicon and fluorine atoms.
Lewis structure shows “is SiF4 polar or nonpolar” from Wikipedia
Silicon tetrafluoride is considered as a Lewis acid. Here the mutual donation of electrons from fluorine and acceptance from Silicon take place, which generates the idea that Si is the Lewis acid, and F atoms are the Lewis bases.
The coordinate covalent bond is created through this reaction. The compound to expand the valances uses the vacant d-orbitals. It is a huge feature, which says that SiF4 is a Lewis acid. The empty d-orbitals are hold by Silicon. Therefore, it cannot be taken as an example of Lewis base.
The drawing process of electron dot structure of the compound depends on the valance possessed by the elements. Valance of Silicon is four and fluorine is seven. Therefore, the total number of valance electron in SiF4 is [4+ (7*4)] = 32. However, by arranging these valance electrons the elements fulfil their octets.
High electronegativity of fluorine does not allow it to be the central atom. Therefore, in Lewis structure Si stays in the centre. By making four single bonds, four fluorine atoms shared two electrons of each with Silicon.
The Lewis structure is reliable in understating the covalent nature of SiF4. The hybridization is SP3 in the compound. This structure informs that the chemical bonding of the molecules are formed by following the theory called “Valance shell Electron pair repulsion (VSEPR)”. The molecular geometry gets proper dimension with the help of this theory.
Dipole moment if SiF4?
Dipole moment refers to the concept of measuring the separation of opposite charges in a compound. This concept is applicable for SiF4 as it has polar bonds and dipole exits among the ionic structure. On the contrary, the measurement of dipole says a exceptional fact about this compound.
The non-polar SiF4 has zero dipole moment, as the dipole moment is cancelled out by the symmetric molecular geometry of Silicon fluoride. The tetrahedral geometry shows that the binds have absolute dipoles. Nevertheless, the moment cancelled put due to the pulling effect in tetrahedral shape.
Question 1: Why does SiF4 possess zero dipole moment?
Answer: the dipole moment of the polar binds in SiF4 is eliminated by the tetrahedral molecular geometry of the compound.
Question 2: Why SiF4 is Covalent?
Answer: The covalent characteristic in SiF4 is noticed as the bond between Silicon and Fluorine atoms are formed by the influence sharing method not complete transfer of electrons. Therefore, the bonds are covalent only.
Question 3: What information shared by the Lewis Structure about the compounds?
Answer: “Valance shell Electron pair repulsion (VSEPR)” theory is informed by the Lewis structure of the compounds. Lewis structure denotes that the molecular geometry is represented by this theory. This theory provides information about the arrangements of electrons regarding the existence of valance shell of the atoms.
Question 4: Compare the molecular geometries of SiF4 and SF4 according to the polarity.
Answer: SiF4 has covalent bonds between Silicon and Fluorine atoms. The bonds are arranged in tetrahedral shape. Moreover, has no lone pair in its molecular geometry. Sp3 hybridization structure possesses vacant d-orbitals in Silicon.
In SF4, the covalent bonds are present in the structure. There is also four bonds created by fluorine atoms by sharing electrons with Sulphur. The main difference of SF4 bonds with SiF4 is that in the molecular geometry of SF4 a lone pair of sulphur exists. It creates strong dipole moment in SF4.The dipole moments are cancelled out by the pulling effect in the bonds in SiF4.
Question 5: Briefly discuss about the bond arrangements in SiF4.
Answer: In SiF4, the bonds exist in tetrahedral geometry by having dipole but due to tetrahedral shape the dipole moment is found to be zero here. As Fluorine is more electronegative in nature, Silicon holds the centre position in this compound and Fluorine atoms creates single bind with it.
Question 6: How SiF4 is a Lewis acid?
Answer: SiF4 holds a vacant d-orbital in the molecular structure, which makes it an electron donor not an acceptor. Therefore, it is considered as a Lewis acid not base.
Sulfur dioxide (SO2) is a chemical compound composed of one sulfur atom and two oxygen atoms. It is commonly found in volcanic gases, industrial emissions, and as a byproduct of certain chemical reactions. One of the key questions surrounding SO2 is whether it is a polar or nonpolar molecule. The polarity of a molecule is determined by the distribution of its electrons and the shape of the molecule. In the case of SO2, the molecule is bent or V-shaped, with the sulfur atom at the center and the two oxygen atoms on either side. This bent shape, along with the electronegativity difference between sulfur and oxygen, leads to the molecule being polar. To understand why SO2 is polar, we need to delve deeper into its molecular structure and the concept of electronegativity.
The molecule has a bent shape due to the presence of two lone pairs of electrons on the sulfur atom.
The difference in electronegativity between sulfur and oxygen atoms creates a dipole moment, making SO2 polar.
The polarity of SO2 allows it to dissolve in polar solvents and exhibit dipole-dipole interactions.
Bond Type of SO2
Sulfur dioxide (SO2) is a chemical compound composed of one sulfur atom bonded with two oxygen atoms. To understand the bond type in SO2, we need to delve into the concept of chemical bonding.
Chemical bonding occurs when atoms share or transfer electrons to achieve a stable electron configuration. In the case of SO2, sulfur has six valence electrons, while oxygen has six valence electrons each. Valence electrons are the electrons in the outermost energy level of an atom that participate in bonding.
Explanation of the Type of Bond in SO2 (Polar Covalent Bond)
In the case of SO2, the bond between sulfur and oxygen is a polar covalent bond. A covalent bond is formed when two atoms share electrons. However, in a polar covalent bond, the sharing of electrons is unequal, resulting in a partial positive charge on one atom and a partial negative charge on the other.
In SO2, the oxygen atoms are more electronegative than sulfur. Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond. Oxygen’s higher electronegativity means it has a greater pull on the shared electrons, resulting in a partial negative charge on the oxygen atoms.
On the other hand, sulfur has a partial positive charge due to the unequal sharing of electrons. This charge distribution creates a dipole moment in the molecule, where one end has a slightly positive charge and the other end has a slightly negative charge.
The Lewis structure of SO2 can help us visualize the bonding arrangement. In the Lewis structure, the sulfur atom is in the center, surrounded by two oxygen atoms. Each oxygen atom is connected to the sulfur atom by a single bond, and there is a lone pair of electrons on the sulfur atom.
The molecular geometry of SO2 is bent or V-shaped, with the sulfur atom at the center and the oxygen atoms on either side. This bent shape is a result of the repulsion between the lone pair of electrons on the sulfur atom and the bonding pairs of electrons.
To summarize, the bond in SO2 is a polar covalent bond. The unequal sharing of electrons between sulfur and oxygen leads to a dipole moment in the molecule, making it a polar molecule. The V-shaped molecular geometry further enhances the polarity of SO2.
In the next section, we will explore the implications of SO2’s polarity and its significance in various applications.
Why is SO2 Polar and SO3 Nonpolar?
When it comes to understanding the polarity of molecules, it is essential to consider the electronegativity difference between the atoms involved, as well as the molecular structure. In the case of sulfur dioxide (SO2) and sulfur trioxide (SO3), the differences in their polarity can be explained by examining these factors.
Comparison of the Electronegativity Difference between Oxygen and Sulfur in SO2 and SO3
Electronegativity is a measure of an atom‘s ability to attract electrons towards itself in a chemical bond. In the case of SO2 and SO3, both molecules contain sulfur and oxygen atoms. Oxygen is more electronegative than sulfur, meaning it has a greater ability to attract electrons towards itself.
In SO2, the electronegativity difference between sulfur and oxygen is significant. This difference creates a polar covalent bond between the sulfur and oxygen atoms. A polar covalent bond occurs when there is an unequal sharing of electrons between two atoms. In this case, the oxygen atom attracts the shared electrons more strongly than the sulfur atom, resulting in a partial negative charge on the oxygen atom and a partial positive charge on the sulfur atom.
On the other hand, in SO3, the electronegativity difference between sulfur and oxygen is not as significant as in SO2. The three oxygen atoms in SO3 are equally electronegative, resulting in a symmetrical distribution of charge. This symmetrical distribution of charge cancels out any dipole moment, making SO3 a nonpolar molecule.
Explanation of the Unequal Charge Separation and Bent Structure in SO2
The unequal charge separation in SO2 can be attributed to its molecular structure. In the Lewis structure of SO2, sulfur is surrounded by two oxygen atoms, forming a bent or V-shaped molecule. This bent structure is a result of electron repulsion between the lone pairs of electrons on the oxygen atoms and the bonding pairs of electrons between the sulfur and oxygen atoms.
The repulsion between the lone pairs and bonding pairs causes the oxygen atoms to push closer together, resulting in a bent shape. This bent shape leads to an unequal distribution of charge, with the oxygen atoms carrying a partial negative charge and the sulfur atom carrying a partial positive charge.
Discussion of the Net Dipole Moment in SO2 Resulting from the Vector Direction of the Bonding Pair Moment towards Oxygen
The unequal charge separation in SO2 gives rise to a net dipole moment. A dipole moment is a measure of the polarity of a molecule and is represented by an arrow pointing towards the more electronegative atom.
In SO2, the dipole moment arises from the vector direction of the bonding pair moment towards the oxygen atoms. The oxygen atoms, being more electronegative, attract the shared electrons towards themselves, resulting in a partial negative charge. This creates a dipole moment with a positive end at the sulfur atom and a negative end at the oxygen atoms.
The presence of a net dipole moment in SO2 indicates that it is a polar molecule. The dipole moment allows for the formation of intermolecular forces, such as dipole-dipole interactions, which contribute to the physical properties of the molecule.
In contrast, the symmetrical distribution of charge in SO3 results in a cancellation of the dipole moments, making it a nonpolar molecule. The absence of a net dipole moment in SO3 means that it lacks the intermolecular forces associated with polarity.
Lewis Structure of SO2
The Lewis structure of a molecule provides a visual representation of how its atoms are bonded together and how the electrons are distributed. In the case of sulfur dioxide (SO2), the Lewis structure helps us understand the arrangement of the atoms and the bonding within the molecule.
Description of the Lewis structure of SO2
The Lewis structure of SO2 consists of a sulfur atom (S) bonded to two oxygen atoms (O). To determine the Lewis structure, we start by counting the total number of valence electrons in the molecule. Sulfur is in Group 6A of the periodic table and has 6 valence electrons, while oxygen is in Group 6A and has 6 valence electrons each. Therefore, the total number of valence electrons in SO2 is 6 (from sulfur) + 2 × 6 (from oxygen) = 18.
Next, we arrange the atoms in the molecule and connect them with single bonds. In the case of SO2, the sulfur atom is in the center, and the two oxygen atoms are attached to it. Each bond consists of a pair of electrons, so we have used 4 valence electrons (2 pairs) to form the two sulfur-oxygen bonds.
After connecting the atoms with bonds, we distribute the remaining valence electrons around the atoms to satisfy the octet rule. The octet rule states that atoms tend to gain, lose, or share electrons to achieve a stable electron configuration with 8 valence electrons. In the case of sulfur and oxygen, they both need 8 valence electrons to achieve a stable configuration.
Since we have used 4 valence electrons for the bonds, we have 18 – 4 = 14 valence electrons remaining. These electrons are distributed as lone pairs on the oxygen atoms. Each oxygen atom can accommodate 6 valence electrons (2 in the bond and 4 as lone pairs), satisfying the octet rule.
The final Lewis structure of SO2 is as follows:
O
/
S = O
\
O
In this structure, the sulfur atom is in the center, and the oxygen atoms are arranged on either side. The bonds between sulfur and oxygen are represented by lines, while the lone pairs of electrons on the oxygen atoms are represented by dots.
Analysis of the lone pair moment and bond pair moment in SO2
In SO2, the presence of lone pairs on the oxygen atoms and the bonding between sulfur and oxygen contribute to the overall molecular geometry and polarity of the molecule.
The lone pairs on the oxygen atoms create a repulsion effect, pushing the atoms slightly away from each other. This results in a bent or V-shaped molecular geometry for SO2. The bond angle between the sulfur-oxygen bonds is approximately 119 degrees.
The electronegativity difference between sulfur and oxygen also plays a role in determining the polarity of the molecule. Oxygen is more electronegative than sulfur, meaning it has a greater ability to attract electrons towards itself. As a result, the oxygen atoms in SO2 have a partial negative charge, while the sulfur atom has a partial positive charge.
The presence of the lone pairs and the unequal distribution of charge in the molecule give rise to a dipole moment in SO2. The dipole moment is a measure of the separation of positive and negative charges in a molecule. In the case of SO2, the dipole moment is non-zero, indicating that the molecule is polar.
To summarize, the Lewis structure of SO2 reveals the arrangement of atoms and electrons in the molecule. The presence of lone pairs on the oxygen atoms and the bonding between sulfur and oxygen contribute to the bent molecular geometry and the polarity of SO2.
Determining the Polarity of SO2
Determining the polarity of a molecule is crucial in understanding its chemical properties and behavior. In the case of sulfur dioxide (SO2), it is essential to assess whether it is a polar or nonpolar molecule. The polarity of SO2 is influenced by several factors, including its geometry, shape, the compactness of electron clouds, the bond dipole moment, and the electronegativity difference between oxygen and sulfur.
Geometry, Shape, and Compactness of Electron Clouds
To determine the polarity of SO2, we must first consider its geometry and shape. The molecular geometry of SO2 is known as bent or V-shaped. This shape arises due to the presence of two electron pairs on the central sulfur atom and the repulsion between these electron pairs. The sulfur atom is bonded to two oxygen atoms, and the molecule has a central sulfur-oxygen-sulfur bond angle of approximately 119 degrees.
The shape of SO2 plays a crucial role in determining its polarity. The presence of lone pairs on the central atom creates an uneven distribution of electron density. The oxygen atoms pull the electron density towards themselves, resulting in a polar molecule.
Application of the VSEPR Theory
The Valence Shell Electron Pair Repulsion (VSEPR) theory is a useful tool in predicting the shape of molecules. According to this theory, electron pairs around a central atom repel each other and arrange themselves in a way that minimizes this repulsion. In the case of SO2, the two oxygen atoms and the two lone pairs of electrons on the sulfur atom repel each other, leading to the bent shape.
The VSEPR theory helps us understand the arrangement of atoms and lone pairs around the central atom, which in turn provides insights into the polarity of the molecule. In the case of SO2, the bent shape indicates an uneven distribution of electron density, making it a polar molecule.
Bond Dipole Moment and Its Contribution to Polarity
The bond dipole moment is another factor that influences the polarity of a molecule. It is a measure of the polarity of a chemical bond within a molecule. In the case of SO2, the sulfur-oxygen bonds are polar due to the difference in electronegativity between sulfur and oxygen.
The bond dipole moment is determined by the electronegativity difference between the atoms involved in the bond. Electronegativity is a measure of an atom‘s ability to attract electrons towards itself. Oxygen is more electronegative than sulfur, causing the oxygen atoms to pull the shared electrons closer to themselves. This creates partial positive charges on the sulfur atom and partial negative charges on the oxygen atoms.
The bond dipole moments in SO2 do not cancel each other out due to the bent shape of the molecule. As a result, the molecule has a net dipole moment, making it a polar molecule.
Electronegativity Difference between Oxygen and Sulfur
The electronegativity difference between oxygen and sulfur is an important factor in determining the polarity of SO2. Electronegativity values range from 0 to 4, with higher values indicating a stronger ability to attract electrons. Oxygen has an electronegativity value of 3.44, while sulfur has an electronegativity value of 2.58.
The significant difference in electronegativity between oxygen and sulfur contributes to the polar nature of SO2. Oxygen’s higher electronegativity causes it to attract electrons more strongly, resulting in partial negative charges on the oxygen atoms and a partial positive charge on the sulfur atom.
Comparison with Other Molecules
When discussing the polarity of SO2 (sulfur dioxide), it is helpful to compare it with another molecule, such as CO2 (carbon dioxide). While both molecules contain atoms bonded together, they exhibit different levels of polarity.
Comparison of the Polarity of CO2 and SO2
CO2 is a nonpolar molecule, meaning it has an equal distribution of charge and no dipole moment. On the other hand, SO2 is a polar molecule, which means it has an uneven distribution of charge and a nonzero dipole moment.
The difference in polarity between CO2 and SO2 can be attributed to their molecular structures and the electronegativity of the atoms involved.
Explanation of Why CO2 is Nonpolar and SO2 is Polar
In CO2, the central carbon atom is bonded to two oxygen atoms through double bonds. The carbon-oxygen bonds are symmetrical, with the same electronegativity for both atoms. As a result, the electrons in the bonds are shared equally, leading to a cancellation of any dipole moment. This equal sharing of electrons creates a nonpolar molecule.
On the other hand, in SO2, the central sulfur atom is bonded to two oxygen atoms through single bonds. Unlike in CO2, the sulfur-oxygen bonds are not symmetrical. The sulfur atom is less electronegative than oxygen, causing the electrons in the bonds to be pulled closer to the oxygen atoms. This unequal sharing of electrons creates a dipole moment, resulting in a polar molecule.
The polar nature of SO2 can also be explained by its molecular geometry. According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, the sulfur atom in SO2 has a bent or V-shaped molecular geometry. This bent shape leads to an uneven distribution of charge, with the oxygen atoms having a partial negative charge and the sulfur atom having a partial positive charge.
Frequently Asked Questions
1. Is SO2 polar or nonpolar?
Sulfur dioxide (SO2) is a polar molecule.
2. What type of bond is SO2: polar or nonpolar?
The bond in SO2 is a polar covalent bond.
3. Why is SO2 polar and SO3 nonpolar?
SO2 is polar because it has a bent molecular geometry and a significant dipole moment, while SO3 is nonpolar due to its trigonal planar molecular geometry and a symmetrical distribution of charge.
4. Does SO2 have polar or nonpolar bonds?
SO2 has polar covalent bonds.
5. Is the Lewis structure of SO2 polar or nonpolar?
The Lewis structure of SO2 indicates that it is a polar molecule.
6. Is SO2 a polar molecule?
Yes, SO2 is a polar molecule.
7. Why is SO2 nonpolar?
SO2 is actually a polar molecule, not nonpolar. It has a bent molecular geometry and a significant dipole moment.
8. Is SO2 polar or nonpolar?
SO2 is a polar molecule.
9. Are CO2 and SO2 polar or nonpolar?
CO2 is a nonpolar molecule, while SO2 is a polar molecule.
When light strikes on a medium, it has to trace a path parallel to the propagation medium or perpendicular to it.
In the previous post, we have given a brief introduction about s polarized waves, which are perpendicular to the direction of propagation.P polarization is the direction of the polarized wave parallel to the propagating medium. Generally, the alignment of the incident wave and the p polarized waves is the same, i.e., both are in the same direction.
Let us discuss how can we achieve p polarization and the cause of p polarized wave in detail.
What is p polarization?
Assume electromagnetic radiation is incident on a dielectric medium such as glass. A part of radiation transmitted through the medium and part of the light reflects due to surface effect, the general polarization process.
Electromagnetic radiation is said to be p polarized when the transmitted radiation is well defined in a single direction parallel to the propagation medium. We can observe the vanishing Brewster’s angle in p polarization.
We know that the transmitted waves are in parallel to the propagating medium; hence the incident wave is also in the exact direction parallel to the medium of propagation.
Light is electromagnetic radiation; hence it can easily undergo polarization when it passes through a polarizing medium.
P Polarized wave
The orientation of the polarized light is characterized to lay parallel to the plane of incidence. The orientation depends on Brewster’s angle as the p polarized light is harder to achieve at Brewster’s angle.
What is p polarized light?
Incident lights are un-polarized; they are randomly distributed in all directions, leading us to the loss of light energy due to certain surface phenomena. To avoid such loss, we use the technique of polarization by bringing the shattered light into one path.
The confinement of the random light into a well-defined direction parallel to the plane of incidence and hence the electric fields are also pointed parallel to the incident plane.
Let us assume that an un-polarized light is randomly distributed on a plane is made to fall on the dielectric medium. As usual, a part gets reflected and partly gets transmitted, resulting in random light radiation tracing a single path. If the interface is perpendicular to the transmitted light direction, the transmitted light traces a path parallel to the propagating medium; this gives the p polarized light.
p polarized wave
We know that all waves cannot undergo polarization; only transverse waves can. One such example of a transverse wave is an electromagnetic wave. Now let us discuss how the p polarization happens in these waves.
Electromagnetic waves combine both electric and magnetic fields laying perpendicular to one another. Since electric fields and magnetic fields are not in phase, we can bring them in phase by polarization. During the process, the unwanted random waves are reflected, and only the waves which can be confined are allowed to transmit. Generally, the p polarization of a wave is referred to as the transverse magnetic polarized wave because, in an electromagnetic wave, magnetic fields are perpendicular to the interface. Hence, they polarized parallel to the meridional plane.
P Polarized Electromagnetic wave
Suppose the electromagnetic wave strikes the medium and get polarized and transmitted through the medium parallel to the plane of incidence, and some of the waves are reflected. The phenomenon takes place between the two mediums of different refractive indices. The tangential component of the electric field and the magnetic field can be resolved as follows;
Let us assume that the electromagnetic wave is transmitting from the medium of refractive index η1 to η2 and θi be the angle of incidence, θr be the angle of reflection and θt be the angle transmission.
Free body diagram describing p polarized EM wave
The tangential component of the electric and magnetic field at the interface of both the medium is
Etan,1 = Etan,2
Htan,1 = Htan,2
For the magnetic field, all the components are tangential, and hence we can write them as
Hi = Hr + Ht
Where Hi is the incident magnetic field, Hr is the reflected magnetic field, and Ht is the transmitted magnetic field.
The tangential vector for the electric field is a bit complicated because all the components are oriented in different directions. They can be written as
Ei cosθi – Er cosθr = Et cosθt
Where Ei, Er and Et are the incidents, reflected, and transmitted electric fields, respectively.
For electric field, the angle of incidence and angle of reflection are same, i.ie., θi=θr; hence the equation can be written as
Ei cosθi – Er cosθi = Et cosθt (1)
The magnetic fields components can be written in terms of electric field as
Ei/η1+Ei/η1=Et/η2 (2)
The ratio of the reflected and transmitted wave with the incident wave gives the required p polarized reflected and transmitted wave as
Er/Ei=r
and Et/Ei = r
Now divide the equations (1) and (2) by Ei we get
Cosθi – r cosθi = t cosθt
1/ηi+r/η1=t/η2
The refractive index can be written in terms of ratio of wave in free space and standard value of refractive index in the medium as
η1=η0/η
Comparing and resolving the equations obtained above we can write the p polarized reflective wave as
rp=η2 cos θi-η1 cos θt/η2 cos θ+η1 cos θt
And the transmitted p polarized wave as
tp=2η2 cos θi/ η2 cos θi+η1 cos θt
The equation obtained above gives the p polarized electromagnetic wave transmitting through a medium. The equations are also called as “Fresnel’s equations for p polarized wave.”
p-polarized incidence
P polarization depends on the wave’s angle of incidence on the interface. As Brewster’s angle vanishes at the interface during the p polarization, the angle of incidence should not be equal to Brewster’s angle.
P polarized waves can be used as an incident wave; this means that p polarized waves are mostly linearly polarized.
If a linearly polarized light wave is incident on the interface of the dielectric medium at Brewster’s angle parallel to the direction of propagating medium, then there would be no reflection taking place on the medium because Brewster’s angle refers to the angle at which no reflection is possible. Hence we can observe complete refraction and transmission of the light wave through the medium when the p polarized wave is used as the incident wave, and thus reflection coefficient will be zero.
p-polarized emission
The emission of the polarized wave is most commonly observed in plasmons. With the help of the photoelectric emission microscope, we can observe the emission of polarized light. The emission of the linearly polarized optical waves is observed in a nanoscale.
Young’s double-slit experiment for high-intensity lasers gives a good account for the p polarized emission. The intensity of the p polarized emission as the function of angle of emission is observed around 597 nm. The electrons with the high energy state emit more rapidly than the lower-energy electrons. For the p polarized emission, the incident p polarized laser should be oblique. The higher energy emitted electrons are accelerated in the polarized direction of the incident laser beam.
P polarized Emission
Can you see circularly polarized light?
Most of us are unaware of our sensitivity towards polarization. Polarization is nothing but the orientation of the light oscillating in a particular direction. We see the pattern of the polarization in the sky, but we cannot recognize them as polarization. Humans can also perceive circularly polarized light with bare eyes.
Human eyes have the ability to detect polarized light. The polarization angle can be detected using a phenomenon called Haidinger’s brushes.
Is p polarization vertical?
Yes, p polarization is vertical. A vertical polarization is corresponds to some arbitrary frame of reference. By considering the direction of gravity, we can say vertical polarization and p polarization are the same.
If we consider the direction of gravity as the propagation medium, then vertically polarized light has the electric field parallel to the direction of the gravity; this means that p polarization is vertical as the polarized wave is parallel to the direction of propagation along with the medium.
However, in some cases the above statement is contradicts what we have assumed. If we choose the propagation of light on the medium considering the gravity direction, p polarization is not vertical, as the electric field is perpendicular to the propagation of the wave.
Thus p polarization is vertical or not depending on the frame of reference. In the laboratory frame we use horizontal direction as the parallel to the propagation.
The concept of polarity in chemistry refers to the distribution of charge within a molecule. When a molecule is polar, it means that there is an uneven distribution of electrons, resulting in a partial positive charge on one end and a partial negative charge on the other. One example of a polar molecule is a tetrahedral molecule. A tetrahedral molecule is a molecule with four atoms bonded to a central atom, arranged in a symmetrical tetrahedral shape. The polarity of a tetrahedral molecule depends on the electronegativity of the atoms involved in the bonding. If the atoms have different electronegativities, the molecule will be polar. On the other hand, if the atoms have similar electronegativities, the molecule will be nonpolar.
Key Takeaways
Molecule
Polarity
CH4
Nonpolar
NH3
Polar
H2O
Polar
CF4
Nonpolar
Understanding Tetrahedral Geometry
Tetrahedral geometry is a molecular geometry that describes the arrangement of atoms in a molecule. It is characterized by a central atom surrounded by four other atoms or groups of atoms, forming a three-dimensional shape resembling a pyramid with a triangular base. This molecular shape is commonly found in many chemical compounds and plays a crucial role in determining the overall structure and properties of molecules.
Definition of Tetrahedral Structure
In a tetrahedral structure, the central atom is bonded to four other atoms or groups of atoms, creating a symmetrical arrangement. This molecular geometry is often observed in compounds where the central atom has four bonding pairs of electrons. The tetrahedral shape is a result of the repulsion between these electron pairs, which strive to be as far apart from each other as possible. This arrangement ensures maximum stability and minimizes electron-electron repulsion.
Bond Angle in Tetrahedral Molecules
The bond angle in tetrahedral molecules is a key characteristic of this molecular geometry. In a perfect tetrahedron, the bond angle between any two adjacent bonds is approximately 109.5 degrees. This angle is known as the tetrahedral angle and is a consequence of the electron pair repulsion theory. According to the theory, the four bonding pairs of electrons repel each other, pushing the atoms away from each other and resulting in the observed bond angle.
Influence of Valence Shell Electron Pair Repulsion Theory on Tetrahedral Geometry
The Valence Shell Electron Pair Repulsion (VSEPR) theory provides a framework for understanding and predicting the molecular geometry of compounds, including tetrahedral molecules. According to the VSEPR theory, the electron pairs around the central atom arrange themselves in a way that minimizes repulsion, leading to specific molecular shapes.
In the case of tetrahedral molecules, the VSEPR theory predicts that the four bonding pairs of electrons will arrange themselves as far apart as possible, resulting in a tetrahedral shape. This theory helps explain the observed bond angle and the overall structure of tetrahedral molecules.
The concept of tetrahedral geometry is crucial in understanding the polarity of molecules. The arrangement of atoms in a tetrahedral molecule can lead to either a polar or nonpolar molecule, depending on the nature of the bonds and the distribution of electrons. If the bonds in a tetrahedral molecule are symmetrical and the electronegativity of the atoms involved is the same, the molecule is nonpolar. However, if the bonds are asymmetrical or if there is a difference in electronegativity, the molecule can be polar.
Polarity in Molecules
Definition and Importance of Polarity
Polarity in molecules refers to the uneven distribution of electron density within a molecule, resulting in a separation of positive and negative charges. This phenomenon is crucial in understanding the behavior and properties of various chemical compounds. The polarity of molecules is determined by factors such as molecular geometry, electron distribution, and the presence of polar bonds.
To comprehend molecular polarity, it is essential to consider the concept of electronegativity. Electronegativity is the measure of an atom’s ability to attract electrons towards itself in a chemical bond. When two atoms with different electronegativities are bonded together, a polar bond is formed. The atom with higher electronegativity will have a partial negative charge, while the other atom will have a partial positive charge.
The overall polarity of a molecule is determined by the combination of polar bonds and the molecular geometry. The arrangement of atoms in a molecule plays a significant role in determining its polarity. The VSEPR (Valence Shell Electron Pair Repulsion) theory helps in predicting the molecular geometry based on the arrangement of electron pairs around the central atom.
Criteria for a Molecule to be Polar
For a molecule to be polar, it must meet certain criteria. Firstly, the molecule should have polar bonds. This means that there should be a significant difference in electronegativity between the atoms involved in the bond. Secondly, the molecular geometry should not be symmetrical. If the molecule has a symmetrical shape, the polarities of the individual bonds cancel out, resulting in a nonpolar molecule.
Let’s take the example of a water molecule (H2O) to understand this concept further. Oxygen is more electronegative than hydrogen, resulting in polar bonds between oxygen and each hydrogen atom. Additionally, the water molecule has a bent or V-shaped geometry, which is not symmetrical. As a result, the polarities of the bonds do not cancel out, making water a polar molecule.
Relationship between Structure and Polarity
The relationship between the structure of a molecule and its polarity is crucial in understanding the behavior of different compounds. The arrangement of atoms and the distribution of electron pairs influence the overall polarity of the molecule.
Molecules with symmetrical structures, such as those with a tetrahedral shape, tend to be nonpolar. This is because the polarities of the individual bonds cancel out due to the symmetrical arrangement. For example, methane (CH4) has a tetrahedral structure, and the carbon-hydrogen bonds are nonpolar, resulting in a nonpolar molecule.
On the other hand, molecules with an asymmetrical structure, such as those with a bent or trigonal pyramidal shape, are more likely to be polar. The presence of lone pairs of electrons or the unequal distribution of atoms leads to an uneven charge distribution within the molecule. For instance, ammonia (NH3) has a trigonal pyramidal structure, and the nitrogen-hydrogen bonds are polar, resulting in a polar molecule.
Key Terms
Molecular geometry
Polarity of molecules
Tetrahedral shape
Molecular polarity
Chemical bonding
Electron pair geometry
VSEPR theory
Dipole moment
Nonpolar molecules
Lewis structures
Valence electrons
Molecular symmetry
Covalent bonding
Electronegativity
Polar bonds
Molecular shapes
Tetrahedral molecules
Polar vs nonpolar
Molecular structure
Electron distribution
Polarity of Tetrahedral Molecules
Tetrahedral molecules are a type of molecular geometry where four atoms or groups of atoms are arranged symmetrically around a central atom. This arrangement creates a tetrahedral shape, which is characterized by a central atom surrounded by four bonding pairs of electrons. The polarity of tetrahedral molecules is determined by the symmetry and electronegativity of the atoms involved.
Symmetrical and Asymmetrical Tetrahedral Geometries
In tetrahedral molecules, the central atom is often bonded to four identical atoms or groups of atoms, resulting in a symmetrical tetrahedral geometry. Examples of symmetrical tetrahedral molecules include methane (CH4) and carbon tetrachloride (CCl4). These molecules have a balanced distribution of electrons, and their dipole moments cancel out, making them nonpolar.
On the other hand, asymmetrical tetrahedral geometries occur when the central atom is bonded to different atoms or groups of atoms. This leads to an unequal distribution of electrons and can result in a polar molecule. An example of an asymmetrical tetrahedral molecule is ammonia (NH3), where the central nitrogen atom is bonded to three hydrogen atoms and one lone pair of electrons.
Polarity in Tetrahedral Molecules Based on Symmetry and Electronegativity
The polarity of a tetrahedral molecule is influenced by both its symmetry and the electronegativity of the atoms involved. Electronegativity is a measure of an atom’s ability to attract electrons towards itself in a chemical bond. When there is a significant difference in electronegativity between the central atom and the surrounding atoms, polar bonds are formed.
In a symmetrical tetrahedral molecule, the electronegativity of the surrounding atoms is usually the same, resulting in nonpolar bonds. However, in an asymmetrical tetrahedral molecule, the electronegativity difference between the central atom and the surrounding atoms can lead to polar bonds. This uneven distribution of electrons creates a dipole moment, giving rise to molecular polarity.
Dipole Moment and Unequal Distribution of Electrons in Tetrahedral Molecules
The dipole moment is a measure of the separation of positive and negative charges in a molecule. In tetrahedral molecules, the presence of polar bonds and an unequal distribution of electrons can result in a non-zero dipole moment. This occurs when the vector sum of the individual bond dipole moments does not cancel out.
For example, in ammonia (NH3), the nitrogen-hydrogen bonds are polar due to the difference in electronegativity between nitrogen and hydrogen. The lone pair of electrons on nitrogen also contributes to the unequal distribution of electrons. As a result, ammonia has a dipole moment and is a polar molecule.
Requirement for a Tetrahedral Molecule to Have a Dipole Moment
To have a dipole moment, a tetrahedral molecule must have an asymmetrical arrangement of atoms or groups of atoms around the central atom. This means that the central atom must be bonded to atoms or groups of atoms with different electronegativities. Additionally, the molecule should not possess any planes of symmetry that would cancel out the dipole moments.
Difference in Electronegativity Leading to Dipole Moment
The difference in electronegativity between the central atom and the surrounding atoms plays a crucial role in determining the dipole moment of a tetrahedral molecule. If the electronegativity difference is significant, polar bonds are formed, resulting in an overall dipole moment for the molecule.
Examples of Polar and Nonpolar Tetrahedral Molecules
Examples of Polar Tetrahedral Molecules
Polar molecules are those that have an uneven distribution of charge, resulting in a positive and negative end. In the case of tetrahedral molecules, the central atom is surrounded by four other atoms, creating a symmetrical arrangement. However, the presence of polar bonds within the molecule can lead to an overall polarity. Let’s explore some examples of polar tetrahedral molecules:
Ammonia (NH3): Ammonia is a commonly known polar tetrahedral molecule. It consists of a nitrogen atom bonded to three hydrogen atoms and one lone pair of electrons. The electronegativity difference between nitrogen and hydrogen creates polar bonds, resulting in an overall dipole moment.
Water (H2O): Water is another example of a polar tetrahedral molecule. It has two hydrogen atoms bonded to an oxygen atom and two lone pairs of electrons. The electronegativity difference between oxygen and hydrogen leads to polar bonds, causing water molecules to have a bent shape and a net dipole moment.
Hydrogen Fluoride (HF):Hydrogen fluoride is a polar tetrahedral molecule composed of a hydrogen atom bonded to a fluorine atom. The electronegativity difference between hydrogen and fluorine results in a polar bond, making the molecule polar overall.
Examples of Nonpolar Tetrahedral Molecules
Nonpolar molecules, on the other hand, have an even distribution of charge and do not possess a net dipole moment. Although tetrahedral molecules tend to have polar bonds, certain factors can lead to a cancellation of the dipole moments, resulting in a nonpolar molecule. Here are a few examples:
Methane (CH4): Methane is a nonpolar tetrahedral molecule. It consists of a carbon atom bonded to four hydrogen atoms. The carbon-hydrogen bonds have similar electronegativities, resulting in a symmetrical distribution of charge and no net dipole moment.
Tetrachloromethane (CCl4): Tetrachloromethane, also known as carbon tetrachloride, is another example of a nonpolar tetrahedral molecule. It contains a carbon atom bonded to four chlorine atoms. The electronegativity of carbon and chlorine is similar, leading to a cancellation of dipole moments and a nonpolar molecule.
Tetrafluoromethane (CF4): Tetrafluoromethane is a nonpolar tetrahedral molecule composed of a carbon atom bonded to four fluorine atoms. The electronegativity of carbon and fluorine is identical, resulting in a symmetrical charge distribution and no net dipole moment.
Comparing Polarity in Other Geometries
When it comes to molecular geometry, the arrangement of atoms in a molecule can greatly influence its polarity. Polarity refers to the distribution of electrons within a molecule, which can result in a molecule having a positive and negative end. In this article, we will explore the polarity of different molecular geometries, including trigonal pyramidal, octahedral, trigonal planar, and bent geometries.
Polarity of Trigonal Pyramidal Geometry
In trigonal pyramidal geometry, the central atom is surrounded by three bonded atoms and one lone pair of electrons. This molecular geometry can be found in molecules such as ammonia (NH3). The presence of the lone pair of electrons creates an uneven distribution of charge, resulting in a polar molecule. The dipole moment in a trigonal pyramidal molecule is not canceled out, making it polar.
Polarity of Octahedral Geometry
Octahedral geometry is characterized by a central atom surrounded by six bonded atoms. This molecular geometry can be found in molecules such as sulfur hexafluoride (SF6). Despite having polar bonds, an octahedral molecule is nonpolar overall. This is because the dipole moments of the polar bonds cancel each other out due to the symmetrical arrangement of the atoms around the central atom.
Polarity of Trigonal Planar Geometry
Trigonal planar geometry is observed when the central atom is surrounded by three bonded atoms and no lone pairs. This molecular geometry can be found in molecules such as boron trifluoride (BF3). In a trigonal planar molecule, the dipole moments of the polar bonds are evenly distributed, resulting in a nonpolar molecule. The symmetrical arrangement of the atoms around the central atom cancels out the dipole moments.
Polarity of Bent Geometry
Bent geometry, also known as angular geometry, occurs when the central atom is surrounded by two bonded atoms and one or two lone pairs. This molecular geometry can be found in molecules such as water (H2O). The presence of lone pairs of electrons creates an uneven distribution of charge, making a bent molecule polar. The dipole moment in a bent molecule is not canceled out, resulting in a polar molecule.
A tetrahedron is not always polar. The polarity of a molecule depends on its molecular geometry and the distribution of its electron pairs. In a tetrahedral molecule, such as CH4 (methane), the molecule is symmetrical, with four identical atoms bonded to a central carbon atom. This symmetrical arrangement results in a nonpolar molecule, as the dipole moments of the polar bonds cancel each other out.
Is Tetrahedral CH4 Polar or Nonpolar?
Tetrahedral CH4 is a nonpolar molecule. As mentioned earlier, the symmetrical arrangement of the four hydrogen atoms around the central carbon atom in methane results in a cancellation of dipole moments. This cancellation occurs because the polar bonds between carbon and hydrogen are arranged symmetrically, leading to a net dipole moment of zero. Therefore, CH4 is considered a nonpolar molecule.
When is a Tetrahedral Molecule Polar?
A tetrahedral molecule can be polar when there is an asymmetrical distribution of electron pairs around the central atom. This occurs when there is a difference in electronegativity between the central atom and the atoms bonded to it. The presence of polar bonds and an uneven distribution of electron density can result in a net dipole moment, making the molecule polar. An example of a polar tetrahedral molecule is NH3 (ammonia), where the nitrogen atom is more electronegative than the hydrogen atoms.
Are Tetrahedral Molecules Always Polar?
No, tetrahedral molecules are not always polar. As mentioned earlier, the polarity of a tetrahedral molecule depends on the distribution of electron pairs and the presence of polar bonds. If the molecule has a symmetrical arrangement of polar bonds, the dipole moments cancel out, resulting in a nonpolar molecule. However, if there is an asymmetrical distribution of electron pairs or polar bonds, the molecule can be polar. It is important to consider both the molecular geometry and the presence of polar bonds when determining the polarity of a tetrahedral molecule.
References
Molecular geometry plays a crucial role in determining the polarity of molecules. The arrangement of atoms and lone pairs around a central atom determines the shape of a molecule. The tetrahedral shape is one of the most common molecular geometries, where the central atom is surrounded by four bonded atoms or electron pairs. This shape is a result of the VSEPR theory, which stands for Valence Shell Electron Pair Repulsion theory. According to this theory, electron pairs around the central atom repel each other and try to maximize their distance, resulting in a tetrahedral arrangement.
The polarity of a molecule depends on the presence of polar bonds and the overall molecular structure. A polar bond occurs when there is a significant difference in electronegativity between the atoms involved in the bond. Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond. When a molecule has polar bonds, the molecular geometry determines whether the molecule is polar or nonpolar.
To understand the polarity of a molecule, we need to consider both the electron pair geometry and the molecular shape. The electron pair geometry describes the arrangement of all electron pairs, including both bonding and nonbonding pairs, around the central atom. On the other hand, the molecular shape only considers the arrangement of atoms, excluding the lone pairs. The presence of lone pairs can affect the molecular shape and, consequently, the overall polarity of the molecule.
In a molecule with a tetrahedral electron pair geometry, the molecular shape can be tetrahedral, trigonal pyramidal, or bent, depending on the presence of lone pairs. If all the electron pairs are bonding pairs, the molecular shape will be tetrahedral. However, if there is one lone pair, the molecular shape will be trigonal pyramidal, and if there are two lone pairs, the molecular shape will be bent.
The dipole moment is a measure of the polarity of a molecule. It is a vector quantity that indicates the separation of positive and negative charges within a molecule. A molecule with a dipole moment is considered polar, while a molecule with no dipole moment is considered nonpolar. The presence of polar bonds does not necessarily mean that the molecule is polar. The molecular symmetry and the distribution of electron pairs play a crucial role in determining the overall dipole moment and, consequently, the polarity of the molecule.
Lewis structures and valence electrons are essential tools in understanding molecular geometry and polarity. Lewis structures represent the arrangement of atoms and valence electrons in a molecule. Valence electrons are the electrons in the outermost energy level of an atom and are involved in chemical bonding. By drawing Lewis structures and considering the arrangement of valence electrons, we can determine the molecular geometry and predict the polarity of a molecule.
Are there any examples of tetrahedral molecule structure?
Yes, there are numerous examples of tetrahedral molecule structures. Tetrahedral geometry occurs when a central atom is bonded to four surrounding atoms, creating a symmetrical four-sided pyramid shape. Examples of tetrahedral molecules include methane (CH4), carbon tetrachloride (CCl4), and silicon tetrafluoride (SiF4). These molecules exhibit tetrahedral geometry, with the central atom bonded to four identical atoms arranged symmetrically around it. For more examples of tetrahedral molecule structures, you can refer to the article on Examples of tetrahedral molecule structure.
Frequently Asked Questions
Is a tetrahedral molecule polar?
A tetrahedral molecule can be polar or nonpolar, depending on the electronegativity of the atoms involved. If the atoms have different electronegativities, the molecule will be polar due to the uneven distribution of electrons, creating a dipole moment. However, if the atoms have the same electronegativity, the molecule will be nonpolar as the electron distribution is even.
Is tetrahedral CH4 polar or nonpolar?
Methane (CH4), which has a tetrahedral shape, is a nonpolar molecule. This is because the hydrogen atoms around the carbon atom are evenly distributed, leading to a balanced distribution of electrons and no net dipole moment.
Why is trigonal pyramidal polar?
A trigonal pyramidal molecule is polar due to its asymmetrical shape and the difference in electronegativity between the central atom and the surrounding atoms. This results in an uneven distribution of electrons, creating a net dipole moment.
How is trigonal planar nonpolar?
A trigonal planar molecule is nonpolar when the surrounding atoms have the same electronegativity as the central atom. This leads to an even distribution of electrons, resulting in no net dipole moment and thus, a nonpolar molecule.
Is octahedral polar or nonpolar?
An octahedral molecule can be polar or nonpolar. If all the surrounding atoms and lone pairs of electrons are identical, the molecule will be nonpolar due to the symmetrical distribution of electrons. However, if there is any difference in the surrounding atoms or lone pairs, the molecule will be polar.
What is tessellation in molecular geometry?
Tessellation in molecular geometry refers to the way in which shapes, like polygons, fit together perfectly without gaps or overlaps. This concept is often used in the study of crystal structures in solid state chemistry.
What is polarization in the context of molecular geometry?
Polarization in the context of molecular geometry refers to the distortion of the electron cloud around an atom or molecule due to the influence of nearby charges. This can lead to the formation of polar bonds and polar molecules.
Why is a tetrahedral molecule sometimes polar?
A tetrahedral molecule is polar when the atoms attached to the central atom are not identical and have different electronegativities. This results in an uneven distribution of electrons, creating a net dipole moment.
Is trigonal bipyramidal polar?
A trigonal bipyramidal molecule can be polar or nonpolar. If the surrounding atoms are identical, the molecule is nonpolar due to the symmetrical distribution of electrons. However, if there is any difference in the surrounding atoms, the molecule will be polar.
An octahedral molecule is polar when there is a difference in electronegativity between the central atom and the surrounding atoms, leading to an uneven distribution of electrons and a net dipole moment.
Is ch2cl2 polar or is it non-nonpolar and whether it is ionic or covalent all these facts and characteristics have been discussed in detail in this article.
We know ch2cl2 is a tetrahedral molecule and not all tetrahedral molecules are polar. But ch2cl2 is a polar molecule and almost all the tetrahedral molecules have a bond angle of 109.5 degrees. All the detailed facts we shall see in the later sections.
Why is ch2cl2 polar?
In simple words, a polar molecule means that one end of the molecule will have a positive charge and the other end will have a negative charge this leads to the formation of a dipole and makes a molecule polar.
Talking about the polarity of Ch2Cl2, yes it is a polar molecule. The important factors that govern the polarity of Ch2Cl2 are shape, dipole moment, and its electronegativity. As these factors help us in determining and understanding the polarity concept of Ch2Cl2, how and why all the reasons and facts have been discussed in the section below.
Ch2Cl2 is also known as dichloromethane (or we can also say methylene chloride). It is an organic compound (molecule). In appearance, it is a liquid (colorless) and its odor is somewhat like chloroform (faint). Its observed density is 1.326 g/cm³ (at a temperature of 20 degrees Celsius) and boils at a temperature of 39.6 degrees Celsius. It is seen to be miscible in alcohol, carbon tetrachloride, benzene, etc.
Coming to its occurrence part, it is found / source in volcanoes, ocean, wetlands, etc. (these are the natural sources of Ch2Cl2). And it is formed in the environment as a result of the emission of industries. We can also prepare it by the reaction of methane (or chloromethane) with chlorine (gas) at a temperature between 410-510 degrees Celsius. Another method of preparation is by reducing chloroform (in presence of Zinc and hydrochloric acid).
Now let’s look at the shape (factor). As we know the shape of a molecule influences polarity of that particular molecule, meaning it plays a very important role in determining polarity. The dipole (net) moment is as a result of the unequal distribution of the electron between the atoms. So there are unequal charges, so they cannot cancel each other and causes the molecule to be polar.
The shape of the Ch2Cl2 molecule is tetrahedral, so it is an unsymmetrical molecule and there is no scope for charges to cancel out. So most of the time a polar molecule will be an asymmetrical molecule we can now say it is a polar molecule.
The next factor is electronegativity. So now we are going to analyse how or what role the concept of electronegativity plays a role in determining the polarity of a molecule. Consider two atoms having the same electronegativity meaning the electron density distribution will be equal. But if the atoms have different electronegativities ( there should be some difference in their electronegativities ) what will happen is the atom among the two having greater/more electronegativity will tend to pull electron density towards itself.
This will create a negative polarity on that side and the other side of the bond will be left with positive electronegativity. So more/greater difference in electronegativity make/increases the polarity, provided the difference should not exceed 1.7 for a covalent bond because beyond that difference a bond is ionic. Hence electronegativity plays important role in increasing the polarity.
Now, let’s have a look at the electronegativities of Ch2Cl2. The electronegativity of the hydrogen is observed to be 2.2, carbon is 2.5 and the chlorine atom has about 3.1. So the difference in their electronegativities is 0.3 for C-H and 0.6 for C-Cl. Hence it confirms that dichloromethane is a polar molecule.
Now, coming to the next factor i.e. dipole moment. The criteria for dipole moment is there should be some amount of difference in the electronegativity of atoms that we are considering. More the difference in electronegativity more will be the dipole moment.
In the earlier section, we have seen the difference in electronegativity of C-H is 0.3 and that of C-Cl is 0.6. So, yes it leads to a dipole moment and the molecule of Ch2Cl2 becomes polar.
So a covalent bond is formed by sharing of electrons. Similar is the case with Ch2Cl2, the bond formed is covalent. And in the earlier section, we have in detail that Ch2Cl2 is polar. Now let’s understand how it is covalent.
Here electronegativity of the molecule will help us determine whether it is covalent or not. If the difference in electronegativity is more than 1.7 a compound or molecule is ionic but if it is less than that it is a covalent compound.
We have seen the difference in electronegativity of Ch2Cl2 does not exceed 1.7 it is less than that (0.3 and o.6 for C-H and C-Cl respectively). Hence we can say Ch2Cl2 is covalent. Yes, Ch2Cl2 is a polar covalent compound.
Ch2Cl2 is a polar covalent bond. Its shape is tetrahedral (asymmetrical), electronegativity difference is not equal (there is a difference of 0.3 and 0.6 for C-H and C-Cl respectively) and there exists a dipole moment. The three factors shape, electronegativity, and dipole moment confirm that Ch2Cl2 is polar.
The bond of Ch2Cl2 is formed covalently. The electronegativity difference does not exceed 1.7 this confirms that it is a covalent bond. Hence we can say Ch2Cl2 is a polar covalent bond.
To understand whether ch2Cl2 is polar protic or aprotic we need to understand this concept in general. A solvent is said to be a polar protic solvent if it has one hydrogen (at least) atom that is linked/connected (directly) to atoms such as OH or NH bond (electronegative atoms ).
For polar aprotic solvents atom of hydrogen is not directly connected to OH or NH (electronegative atoms ) meaning not capable of forming a hydrogen bond. Some common examples of polar aprotic solvents are acetone, DMF, HMF, etc.
Now coming to the structure of ch2Cl2 can we see any link of a hydrogen atom to an electronegative atom such as OH or NH? No there is no such linkage in it. Hence it is not capable of forming a hydrogen bond. So we can say Ch2Cl2 is polar aprotic.
Is ch2cl2 more polar than chcl3?
As we know electronegativity plays a very important role in determining polarity along with dipole moment and shape. The shape of both Ch2Cl2 and ChCl3 is tetrahedral so we cannot use the factor (shape ) to determine the extent of more polarity in this case.
But it has been observed that the electronegativity is more in Ch2Cl2 than ChCl3. Next coming to the dipole moment, the dipole moment in Ch2Cl2 is observed to be 1.6 debye and that of CHCl3 is 1.01 debye. The more the dipole moment, the more polar will be the molecule.
We can see clearly that the dipole moment of dichloromethane is more than that of ChCl3. Hence it is now confirmed Ch2Cl2 is more polar than CHCl3.
Is ch2cl2 soluble in water?
We know water is a polar solvent and polar-polar molecules are well miscible. Yes, Ch2Cl2 is soluble in water but moderately 2g/100 mL at a temperature of 20 degrees Celsius. But Ch2Cl2 is better miscible in organic solvents (alcohols, benzene, etc.).
Solubility of a molecule differs in air and liquids at different temperatures, so the solubility of ch2cl2 will also be different in various mediums at different temperatures .
Is ch2cl2 protic?
No, Ch2Cl2 cannot be protic as for a solvent to be protic it should have (at least) one hydrogen linked to electronegative atoms( OH or NH ) and be able to form a hydrogen bond . This is not the case with Ch2Cl2 as it does not have any hydrogen and electronegative atom linkage and hence no hydrogen bonding. Therefore Ch2Cl2 is protic.
Polarization is the process of aligning the unpolarized electromagnetic wave in one direction. This process of alignment into a single direction corresponds to the nature of the incident wave on the medium.
Based on the nature of the incident wave striking the medium, the polarization of the wave can be said to s polarized or not. The propagation of an s polarized wave is the same as the normal polarized wave, but the incidence of the wave on the medium makes the wave classified as s-polarized. A brief introduction to s-polarized waves is discussed in this post.
What is s polarized light?
If a shattered electromagnetic wave, say the light wave, is made to transmit through a plane medium, the light is confined into a single direction.
When the incident light is in the direction perpendicular to the plane of propagating medium, and then it confines the light wave to achieve a single direction of propagation, such a polarization of light is called s polarized light.
Illustration of s polarized light
Suppose an unpolarized light wave is an incident on a dielectric medium; after transmitting in the medium, the incident light wave traces a well-defined path in a single direction, causing the polarization if the polarization takes place perpendicular to the medium the polarization nothing but s polarization.
The light which has to be s polarized should be perpendicular to the plane of incidence and parallel to the interference.
If the incident light is monochromatic, the state of polarization of light involves the non-zeros components at the planar interface generates the field in the rarer medium whose polarization will be elliptical.
s-polarized light reflection
When the light gets polarized, not all the waves of light are transmitted through the medium. Some of the light waves may be reflected by the plane medium.
The reflection of s polarized light depends on Brewster’s angle as the incident angle. The s polarized light undergoes total internal reflection (TIR) at a dielectric interface at the angle of incidence ψ. Since at Brewster’s angle, no reflection takes place, the angle of incidence must be less or greater than Brewster’s angle.
For expected propagation of incident light perpendicular to the interface of the medium, the s polarized light shows reflectivity. The s polarized light component is not perpendicular to the electric field components; thus, light propagating with Brewster’s angle must undergo total internal reflection.
Gauss law states that “the electric field must be continuous except in the presence of charge.” But for s polarized light, the electric field in the incident and transmitted layers is not equal. Thus electric field shows discontinuity, so there will be the reflection of s polarized light due to the exhibiting the different amplitudes of the electric field in the transmission medium.
Figure illustrating s polarized light reflection
The formula can give the angle of reflection of s polarized light
tanθp=n2/n1
Where θp is the reflected angle and n1, and n2 is the refractive indices of the medium, since the transmission of polarized light is taking place from one medium to another medium.
The equation can also be written as
sinθp/cosθp=n2/n1
Since the above equation is similar to Snell’s law, it can be rewritten as
sinθp/sinr=n2/n1
Because cos θp = sin r, the angle of reflection. Thus we get the equation as
sin π/2-θp=sinr
θp+r= π/2
The above equation gives the reflection of the s polarized light.
s-polarized incident light
If the linear polarization of incident light itself s polarized then the polarized, then there will be the complete transmission of the light through the medium.
When the s polarized light is incident on the dielectric medium, the refraction of the polarized light can be observed. The incident light refracts into two beams. One refracted beam is oriented parallel to the transmission medium, and another one is perpendicular to the transmission medium.
Thus we can use the polarized filter to block the two refracted rays to produce the image. The light is entirely blocked by the polarized filter producing the bright image of the perpendicular component, and the second image will appear when the filter is turned 90°.
s polarized wave
The term polarization is possible only in electromagnetic waves and radio waves. Since, in the case of an electromagnetic wave, the electric field and the magnetic field are oriented in different directions perpendicularly, the polarization can be easily monitored.
S polarized electromagnetic wave
In this section, let us learn what is s polarized wave and the nature of s polarized wave.
What is s polarized wave?
Since we are talking about the wave, we will consider the electromagnetic wave because the electromagnetic wave is an excellent example of the transverse wave. The electromagnetic wave incident on the medium is confined into a single direction, i.e., both electric field and magnetic field, causing the polarization.
If the electromagnetic field hits the medium and it begins transverse perpendicular to the plane of incidence, then the wave is said to be s polarized wave. The amplitude of the wave increases with the angle of incidence increases in the s polarized wave.
Suppose an electromagnetic wave of E and B field is incident on the plane medium, a part of the wave is transmitted, and a part of the wave is reflected in the same medium as shown in the figure.
The electric field vector for the above oscillation of the electric field is given by
E→=x→ A sin (wt – kz)
Where; A is the amplitude of the wave and k is the propagation vector.
The electric field vector is perpendicular to the plane of incidence; thus, the polarized wave is called an s polarized wave. The propagation vector has three components KI, Kr, KT; these are the propagation vectors of the angle of incidence, reflection and transmission of the s polarized wave.
s-polarized dipole
When a minimal distance holds two equal and opposite charges, the arrangement is called a dipole. Suppose a dielectric material is kept on an electric field; the field induces the electric dipole and holds them in the direction of the field. The external electric field is also involved in the process of aligning the electric dipole in the field direction; this entire process is called dipole polarization.
When the electric dipole induced by the field is perpendicular to the plane of propagation, then the polarization is known as s polarized dipole. In this case, polarizability, the negatively charged particles are slightly moved away from the positively charged particle so that the molecule acquires an electric dipole moment.
Frequently Asked Questions
Does s polarized lights are linearly polarized?
The light is linearly polarized when the electric field of light is restricted to propagate in a single direction along the plane of propagation.
If the s polarized light is allowed to move only in the direction of propagation without the phase shift, then the s polarized lights are said to be linearly polarized. Generally, if the incident light wave and the transmitted light waves are in phase, perpendicular to the propagation plane are linearly s polarized light.
Can we get circularly s polarized light?
The circularly polarized lights have the 90° phase shift with the incident light-medium.
If the polarized light is out of phase at 90° and propagates normal to the plane of incidence, then we get the circularly polarized light as a component of s polarized light. The magnitude and the amplitude of the polarized light are equal with the incident light; only there will be a shift in the phase of the polarized light.
Does laser beams are polarized?
Most of the laser beams are polarized, but some of the lasers are un-polarized. It depends on the nature of designing the optics of the laser source.
Laser beams are confined to a single direction and are coherent. Point them on the white paper in a dark room if you have a laser. Rotate the paper; if the brightness of the laser spot changes, then the laser source is partially polarized. If the brightness remains the same, the laser beams are almost polarized. It isn’t easy to achieve an utterly polarized laser.
Can we achieve complete transmission of incident light by polarization?
Due to some surface phenomena, the complete transmission of incident light through polarization is hard to achieve.
Polarization refers to holding up randomly distributed light waves in one single direction. The confinement of all the light rays which strikes the medium is not possible becomes some of the light rays may get reflected from the medium before they get confined.
What are the methods used for polarizing the light?
Generally, there are four methods used to polarize the unpolarized light, which used a specific medium to execute their action; they are
Polarization by Polaroid filters -uses particular dichroic material that absorbs the unwanted unpolarized lightwave and transmits only the suitable light rays.
Polarization by reflection –they use the non-metallic medium to prevent un-polarized light propagation from confining them.
Polarization by refraction – they use two material mediums of different refractive indices for polarizing the shattered light.
Polarization by scattering – involves the propagation of un-polarized light to travel on through a medium that can absorb and reemit light.
A wave can undergo many phenomena such as reflection, refraction, diffraction, and dispersion, which you already know from our previous articles. One among such wave phenomena is polarization.
Polarization is the property of the electromagnetic wave that confines the shattered waves into a single direction. The polarization is further classified into s-polarized and p-polarized by considering the behavior of waves on the plane of propagation. This post is concerned with a comparative analysis of s polarized vs p polarized wave.
Comparison of s polarized vs p polarized wave
Not all wave has the ability to undergo polarization. There are some restrictions for the wave to undergo polarization; such properties are discussed in the table below, giving a brief comparison of s polarized vs p polarized wave.
S polarized
P polarized
Definition
When electromagnetic radiation is incident on a plane medium, the polarization of radiation will occur perpendicular to the plane of incidence; such polarization is called as s polarized.
When an electromagnetic radiation incident on a plane medium, the polarization of the radiation occurs parallel to the plane of incidence, such polarization is called p polarized.
Nature of angle of incidence
In most cases, when an incident wave is made to fall on the polarizer at an angle equal to Brewster’s angle, one can achieve an s-polarized wave.
At Brewster’s angle, we cannot achieve the p polarized wave. The angle of incidence must be greater or less than Brewster’s angle.
Variation of Brewster’s angle
The Brewster’s angle does not affect by the s-polarization; it remains as usual with the incident wave.
The Brewster’s angle vanishes as the wave incident on the plane medium
Reflective ability
As the angle of incidence increases, the ability to reflect the wave also increases in s polarized wave.
There will be no reflection occurring at Brewster’s angle. Almost up to 90°, the reflection is less. As the angle incidence increases above 90°, the reflective ability slightly increases.
Phase difference
There will always be a 180° phase shift of the polarized wave with the incident wave, Brewster’s angle does not matter for the phase difference in s polarized wave.
In the case of a p polarized wave above Brewster’s angle, the phase difference can be seen in a p polarized wave. There will be a 180° phase shift with the incident wave, but below the Brewster’s, the polarized wave is in phase with the incident wave.
The amplitude of the reflected wave
The amplitude of the reflected wave increases with the incidence angle in s polarized wave.
In the case of a p polarized wave also the amplitude of the reflected ray gradually increases with the angle of incidence.
Comparative analysis of s polarized vs p polarized wave
Free body diagram illustrating s polarized vs p polarized wave
Facts to be remember
S polarized, and P polarized waves are essential properties for the reflection and transmission of waves in the medium.
The terms s and prefers to their alignment in the medium. S refers to Senkrecht, which is derived from the German word that means perpendicular or normal, whereas P refers to parallel, based on the alignment of wave incident on the medium.
In the diffraction grating, the s polarized wave refers to the perpendicular polarization with respect to the lines on the grating, not to the perpendicular to the plane of incidence.
If you consider the prism of Brewster’s angle, the reflected ray staying in the horizontal direction is considered to be s polarized because if you tilt the prism, the reflected rays go upward, but it does not change.
The nature of polarization as s polarized and p polarized is considered according to the direction polarization with respect to the plane of incidence. Thus s and p polarized waves must be relevant to the plane of incidence.
Frequently asked questions
What is meant by polarization?
When a wave undergoes any phenomena such as reflection, refraction, diffraction, etc., the waves can propagate in any direction. These waves have not bounded to propagate in a particular direction.
Polarization is the process applied to the waves to bring all the scattered waves in a single proper direction. The longitudinal waves cannot undergo polarization; only the transverse wave can be polarized. The polarization involves the transverse waves to specify the geometrical orientation.
What are the conditions required for polarization?
A wave has to possess several properties to undergo polarization. Some of such conditions are listed below.
A wave should be a transverse wave to undergo polarization.
The wave must be coherent, and the phase difference of the incident wave should be constant.
The medium of propagation should be homogenous.
The wave should be perpendicular to the direction of propagation.
Can sound waves undergo polarization?
We have understood that only transverse waves can undergo polarisation from the definition of polarization. However, the sound wave is a longitudinal wave; it cannot undergo polarization.
Sound waves cannot undergo polarization because the sound wave vibrates only in a single direction, along the direction of propagation. Thus it becomes quite difficult to confine the wave. Hence sound waves cannot be polarized.
An only transverse waves can undergo polarization; explain why?
A wave is said to be transverse when the wave oscillates along the path at a right angle to the direction of propagation.
The transverse wave can vibrate in the direction perpendicular to the energy level so that vibration can occur in all the perpendicular directions, and it becomes easy to confine them. So for transverse waves, there could be two orthogonal directions for propagation in three-dimensional space.
What is meant by Brewster’s angle?
When a light incident on a transparent dielectric medium, the maximum amount of light get polarized at a certain angle, that angle of incidence is nothing but Brewster’s angle.
Brewster’s angle is more precisely stated as it is an angle of incidence at which the wave can perfectly transmit along the transparent surface without letting back reflection of the wave so that one can get the maximum amount of polarized wave.
Linearly polarized wave – the wave is restricted to a single plane along the direction of wave propagation.
Circularly polarized wave – the wave has two linear components perpendicular to each other. Their amplitudes are equal with a phase difference of π/2, resulting in the circular motion of the polarized wave.
Elliptically polarized wave – the wave has two linear components whose amplitudes and phase differences are unequal, resulting in the elliptical motion of the polarized wave
