calcium hydride is an alkaline earth hydride that, when heated, reacts with water liberating hydrogen gas. It is used as a drying agent or desiccant.

Commercially, it is made by heating calcium metal at about 300 degC in a high alloy steel covered crucible with 101 kPa (1 atm) of dry hydrogen gas under controlled conditions. It is a greyish-colored powder or crystalline solid that is insoluble in any solvent with which it does not react vigorously. It is also known as Hydrolith or Hydrith.

The hydride is an extremely potent reducing agent and has been used for producing pure hydrogen in laboratories for many years for various experiments. It is a strong irritant to the skin, eyes and respiratory tract and ingestion may cause vomiting and diarrhoea. If inhalation occurs it may result in bronchitis and oedema of the lungs. This compound is corrosive to copper and silver, it stains teeth and nails and can form explosive mixtures with certain acids and alcohols.

It is a hazard to store as it is very flammable, decomposes upon heating, and is highly toxic. It is incompatible with oxidizing agents, strong acids, halogens and water and reacts violently or explosively with many solvents including water vapor, steam and benzene. It is a moisture sensitive material and should be stored in closed containers away from heat and naked flames. Wear NIOSH approved splash goggles, chemical resistant gloves and a synthetic apron while handling this product.