[Products Name] Calcium Hydride
[Molecular Formula] CaH2
[CAS No.] 7789-78-8
[Product Description]
Calcium hydride is the chemical compound with the formula CaH2. This grey powder (white if pure, which is rare) reacts vigorously with water liberating hydrogen gas. CaH2 is thus used as a drying agent, i.e. a desiccant.
CaH2 is a saline hydride, meaning that its structure is salt-like. The alkali metals and the alkaline earth metals all form saline hydrides. A well-known example is sodium hydride, which crystallizes in the NaCl motif. These species are insoluble in all solvents with which they do not react because they have extended structures. CaH2 crystallizes in the PbCl2 motif.
[Application]
Calcium hydride was, in the 1940s, available under the trade name "Hydrolith" as a source of hydrogen:
The trade name for this compound is "hydrolith"; in cases of emergency, it can be used as a portable source of hydrogen, for filling airships. It is rather expensive for this use.
The reference to "emergency" probably refers to wartime use. The compound has, however, been widely used for decades as a safe and convenient means to inflate weather balloons. Likewise, it is regularly used in laboratories to produce small quantities of highly pure hydrogen for experiments.
Looking to the future, Calcium hydride is a possible source of hydrogen for fuel cells but the use of sodium borohydride in the Direct borohydride fuel cell may be preferable.
