Calcium hydride

Calcium hydride

CaH2 granules
Names
IUPAC name Calcium hydride
Other names Calcium(II) hydride Calcium dihydride
Identifiers
Jmol-3D images	Image
SMILES [H-].[H-].[Ca+2]
Properties
Chemical formula	CaH2
Molar mass	42.094 g/mol
Appearance	White (pure) or gray (impure) powder
Density	1.70 g/cm3
Melting point	816 °C (1,501 °F; 1,089 K)
Boiling point	Decomposes
Solubility in water	Reacts
Solubility	Reacts with alcohols, carboxylic acids Insoluble in common solvents
Vapor pressure	~0 mmHg
Thermochemistry
Std molar entropy (So298)	41.4 J·mol−1·K−1
Std enthalpy of formation (ΔfHo298)	−181.5 kJ·mol−1
Hazards
Safety data sheet	ApolloScientific
Related compounds
Related compounds	Lithium hydride Sodium hydride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Calcium hydride is the chemical compound with the formula CaH₂, widely used as a drying agent, especially in drying solvents.

Properties

Chemical

Calcium hydride reacts with water to release hydrogen gas:

CaH₂ + H₂O → Ca(OH)₂ + H₂ ↑

Physical

Calcium hydride is a grey or white solid powder, insoluble in all solvents. It reacts vigorously with water and alcohols. CaH₂ has a density of 1.70 g/cm³.

Availability

CaH₂ is sold by various chemical suppliers.

Preparation

Calcium hydride can be made by reacting dry hydrogen gas with calcium metal at temperatures between 300 to 400 °C.

Projects

• Dry solvents
• Readily hydrogen source

Handling

Safety

Calcium hydride reacts with water, releasing flammable hydrogen gas.

Storage

Calcium hydride is best stored in closed and airtight containers.

Disposal

A simple way of neutralizing calcium hydride is to add it slowly in a large volume of water, in a well ventilated area. A slower, but safer way is to expose calcium hydride to water vapors. Instead of water, long chain alcohols can also be used to neutralize this compound.

References

Relevant Sciencemadness threads

• Calcium Hydride