Phosphorus Trichloride(PCl3) Properties(25 Facts)

Phosphorus trichloride is an inorganic compound with strong odour. Let us explore it in detail in this article.

Phosphorus trichloride consists of central atom Phosphorus and three surrounding chlorine atoms. It is prepared by the reaction between chlorine and white phosphorus. It has a standard enthalpy of formation of -319.7 kJ/mol. It has a trigonal pyramidal shape.

Let us discuss Chemical classification, CAS number, ChemSpider ID, molar mass, viscosity and other important properties in this article.

Phosphorus trichloride IUPAC name

The IUPAC name of PCl₃ is Trichlorophosphane.

Phosphorus trichloride chemical formula

The chemical formula of Phosphorus trichloride is PCl₃.

Phosphorus trichloride CAS number

The CAS Phosphorus trichloride is 7719-12-2.

Phosphorus trichloride ChemSpider ID

The ChemSpider ID of PCl₃ is 22798.

Phosphorus trichloride chemical classification

The chemical classification of PCl₃ is as follows-

• PCl₃ is an inorganic compound.
• It has a chemical formula PCl₃.
• It is a phosphorus halide with one P and three Cl atoms.
• It is a covalent compound with bond length 204 pm.                  

Phosphorus trichloride molar mass

PCl₃ has a molar mass of 137.33 g/mol.

Phosphorus trichloride color

The PCl₃ is colourless (when pure) or sometimes yellow liquid.

Phosphorus trichloride viscosity

The viscosity PCl₃ is 0.65 cP at 0^οC and 0.438 cP at 50^οC.

Phosphorus trichloride molar density

The molar density of PCl₃ is 1.574 g/cm³.

Phosphorus trichloride melting point

The melting point of PCl₃ is -93.6^οC or 179.6 K.

Phosphorus trichloride boiling point

The boiling point of PCl₃ is 76.1^οC or 349.2 K

Phosphorus trichloride state at room temperature

PCl₃ exists as colourless or a yellow oily liquid at room temperature.

Phosphorus trichloride ionic/covalent bond

PCl₃ consists of three covalent bonds. As both P and Cl are non-metals, they do not have tendency to donate electrons. Thus, P and Cl forms covalent bonds.

Phosphorus trichloride covalent radius

In PCl₃, P atom has a covalent radius of 106 pm while Cl has covalent radius of 99 pm.

Phosphorus trichloride electron configurations

The electronic configuration of P is [Ne] 3s² 3p³. The electronic configuration of Cl is [Ne] 3s² 3p⁵.

Phosphorus trichloride oxidation states

In PCl₃, the oxidation state of P is +3 while the oxidation state of Cl is -1.

Phosphorus trichloride acidity/alkaline

PCl₃ is a Lewis base (alkaline) because the central atom P has a lone pair of electrons which it can donate to a Lewis acid.

Is Phosphorus trichloride odourless?

PCl₃ has a pungent odour like HCl.

Is Phosphorus trichloride paramagnetic?

A diamagnetic substance contains no unpaired electrons while a paramagnetic substance contains unpaired electrons.

PCl₃ is diamagnetic in nature because it does not contain unpaired electrons.

Phosphorus trichloride hydrates

PCl₃ undergoes hydrolysis with water to form phosphorous acid and hydrochloric acid.

PCl₃ + 3H₂O –>H₃PO₃ + 3HCl

Phosphorus trichloride crystal structure

In PCl_3, the central atom P is sp³ hybridized so the crystal structure of PCl₃ is trigonal pyramidal with a bond angle of 103^ο.

Phosphorus trichloride polarity and conductivity

• PCl₃ is polar molecule because high electronegativity of Cl atoms than P, pull electrons of the centre P atom. It has a dipole moment of 0.97 D.
• PCl₃ does not conduct electricity because no ions or no mobile electrons are available to carry current.

Phosphorus trichloride reaction with acid

PCl₃ reacts with organic acid like CH₃COOH to form acyl chloride (CH₃COCl) and H₃PO₃.

CH₃COOH + PCl₃ –> CH₃COCl + H₃PO₃

Phosphorus trichloride reaction with base

PCl₃ reacts with ethanol in the presence of base R₃N (tertiary amine).

POCl₃ + 3 EtOH + 3 R₃N –> P(OEt)₃ + 3 R₃NH⁺Cl^–

Phosphorus trichloride reaction with oxide

PCl₃ reacts with sulphur trioxide to form Phosphorus Oxychloride (POCl₃) and sulfur dioxide(SO₂).

PCl₃ + SO₃ –> POCl₃ + SO₂

Phosphorus trichloride reaction with metal

PCl₃ is used to electrodeposit metal on the rubber.

Conclusion:

PCl₃ is a covalent compound consisting of three covalent bonds. It is a diamagnetic in nature. It exists as liquid at room temperature.