1) Metal hydride 
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 ...
CaH2 Molar mass: 42.09388
[n] - a salt-like binary compound (CaH2) used as a reducing agent and source of hydrogen
hydrolith noun a saltlike binary compound (CaH2) used as a reducing agent and source of hydrogen