text: Calcium disilicide (CaSi) is an inorganic compound, a silicide of calcium. It is a whitish or dark grey to black solid matter with melting point 1033 °C. It is insoluble in water, but may decompose when subjected to moisture, evolving hydrogen and producing calcium hydroxide. It decomposes in hot water, and is flammable and may ignite spontaneously in air.
  Industrial calcium silicide usually contains iron and aluminium as the primary contaminants, and low amounts of carbon and sulfur.