Magnesium hydride(MgH2) Properties(25 Facts You Should Know)

Magnesium hydride is one of the important compounds of magnesium. Let us learn more about Magnesium hydride’s important properties.

Magnesium hydride is an ionic compound with a high potential for hydrogen storage due to its high density. It is used in various forms, including alloys and combinations with materials like carbon nanotubes or catalytic additives for hydrogen storage.

Now let us explore Magnesium hydride’s nomenclature, important properties, and structure.

Magnesium hydride IUPAC name

The IUAPC name of Magnesium hydride is magnesium hydride.

Magnesium hydride chemical formula

The chemical formula of Magnesium hydride is MgH2.

Magnesium hydride CAS number

The CAS number of MgH2 is 7693-27-8.

Magnesium hydride ChemSpider ID

The ChemSpider ID of MgH2 is 16787263.

Magnesium hydride chemical classification

MgH2 is chemically classified as,

  • Ionic compound
  • Alkaline earth metal hydride.    

Magnesium hydride molar mass

Magnesium hydride’s Molar Mass is 26.3207. The calculation is shown below,

Molar mass of MgH2=MMg+2*MH =24.305+2*1.00784 =26.3207.

Magnesium hydride color

The color of MgH2 is white.

Magnesium hydride viscosity

MgH2‘s viscosity is not measured since it decomposes upon heating.

Magnesium hydride molar density

The molar density of MgH2 is 0.0550897 mol/cm3 since its density is 1.45 g/cm3.

Magnesium hydride melting point

The melting point of MgH2 is 307 °C, although it will start decomposing and producing H­­­2 and Mg metal at high temperatures.

MgH2 → Mg + H­2

Magnesium hydride state at room temperature

MgH2 is a white crystalline solid at room temperature.

Magnesium hydride ionic bond

MgH2 is an ionic compound; an ionic bond is formed between Mg2+ and H- ions by the complete transfer of electrons.

magnesium hydride
Magnesium hydride

Magnesium hydride ionic radius

The radius is not defined for MgH2 since the Ionic radius is defined and measured only for atoms, not for an ionic compound containing three ions.

Magnesium hydride electron configurations

Electron configurations show the electrons distributed in an atomic or molecular orbital. Let us learn about the electronic configuration of different atoms in magnesium hydride.

The electron configuration of Mg2+ in Magnesium hydride is 1s2 2s2 2p6, which can also be written in terms of noble gas configuration as [Ne]3s0. The electron configuration of Hin Magnesium Hydride is 1s2.

Magnesium hydride oxidation state

The Mg atom in MgH2 is in a +2 Oxidation state. The H atom is in an oxidation state of -1.

Magnesium hydride alkaline

MgH2 by itself is alkaline, but it rapidly reacts with H2O to form Mg(OH)2 hydrate,

MgH2 + 2 H2O → 2 H2(↑) + Mg(OH)2

Is Magnesium hydride odourless

Magnesium hydride is highly reactive and corrosive and may cause irritation and corrosion if inhaled, and it is strongly advised not to inhale Magnesium Hydride.

Is Magnesium hydride paramagnetic

The atoms/molecules with an unpaired electron in their atomic or molecular orbital are paramagnetic. Let us learn if MgH2 is paramagnetic.

Magnesium Hydride is not paramagnetic because all the Magnesium hydride’s electrons are paired in both Mg2+ and Hions.

Magnesium hydride hydrates

MgH2 does not form any hydrates as it reacts rapidly with water.

MgH2 + 2 H2O → 2 H2(↑) + Mg(OH)2 +2HCl→MgCl2+2H2O

Magnesium hydride crystal structure

MgH2 has a rutile structure at room temperature and pressure, and the form is known as α-MgH2. At high pressure, four different forms of MgH2 have been characterized.

  • γ-MgH2 has an orthorhombic structure and belongs to the space group Pbcn.
  • β-MgH2 has a cubic structure that belongs to the Pa-3 space group.
  • An orthorhombic form with a Pbc2 space group was also found at high pressure.
  • Another orthorhombic form with the Pnma space group was also found at high pressure.

Magnesium hydride polarity and conductivity

  • Magnesium hydride is a polar compound since it involves the transfer of electrons from Mg to H atoms.
  • Magnesium hydride does not conduct electricity since it has no free electrons.

Magnesium hydride reaction with acid

MgH2 does not directly react with acids. Upon exposure to water, it will rapidly form Mg(OH)(magnesium hydroxide), which then reacts with any acids.

MgH2 + 2 H2O → 2 H2(↑) + Mg(OH)2 +2HCl→MgCl2+2H2O

Magnesium hydride reaction with base

MgH2 does not react with bases because they are alkaline in nature.

Magnesium hydride reaction with oxide

MgH2 reacts with some oxides to reduce them; These reductions are accelerated by using a suitable transition metal catalyst such as Cobalt.

2MgH2 + CO2 ->2 MgO + CH­4


We learned about Magnesium hydride, a highly reactive compound particularly useful as a portable hydrogen medium for fuel cells and reductions. They do not react with acids. Formation of hydrates is impossible with water as it reacts rapidly.