Calcium Antimonide, Ca₃Sb₂

When antimony and calcium are heated together they combine so energetically that the resulting Calcium Antimonide, Ca₃Sb₂, is fused by the heat of the reaction. Lebeau prepared it in the electric furnace. On treating with water it gives no antimony hydride, because the heat of reaction is so great as to raise the temperature of the products above the decomposition temperature of the hydride. By reducing calcium chloride with an alloy of sodium and antimony a product is obtained containing 7.6 per cent, of calcium, and giving, on treatment with water, hydrogen containing a large amount of antimony. Calcium Pyrothioantimonite, Ca₂Sb₂S₃.15H₂O, is obtained by dissolving antimony sulphide in calcium hydrosulphide. On evaporating in vacuo beautiful, colourless, triclinic crystals separate. These are soluble in water without decomposition. By concentrating the hot solution a red crystalline compound, SbS₂.CaOH, is formed.