Characteristics: Moderately soft, silver-white, crystalline metal; oxidizes in air to form adherent protective film; can be machined, extruded, or drawn. Soluble in acid; decomposes in water to liberate hydrogen. Sublimes below its melting point in vacuum. Brinell hardness 17.
Derivation: Electrolysis of fused CaCl2; by thermal process under high vacuum from lime reduced with aluminum. Does not occur free in nature.
Hazard: Evolves hydrogen on contact with moisture. Flammable in finely divided state; fire and explosion hazard when heated or on contact with strong oxidizing agents. Nontoxic.