Calcium bromide is an inorganic salt with the molecular formula of CaBr2. It is colorless rhombic acicular crystal or crystal block, odorless, salty and bitter. Relative density 3.353 (25 ºC). It is extremely soluble in water, the aqueous solution is neutral, soluble in ethanol, acetone and acid, slightly soluble in methanol and liquid ammonia, and insoluble in ether or chloroform. It can form double salt with alkali metal halide. It has strong hygroscopicity. It is used in oil drilling, and also in the manufacture of ammonium bromide and photosensitive paper, fire extinguishing agent, refrigerant, etc. It is used medicinally as a central nervous depressant with inhibitory and sedative effects to treat neurasthenia, epilepsy and other diseases.