Nickel Triphosphide, NiP₃

Nickel Triphosphide, NiP₃, results on heating an alloy of nickel and tin, containing 5 per cent, of nickel, with more than 20 per cent, of its weight of phosphorus in a sealed tube to 700° C. Tin triphosphide, SnP₃, is simultaneously produced, but may be decomposed by heating the mixture under reduced pressure at 860° C. Treatment with hydrochloric acid removes the products, leaving the triphosphide as a crystalline residue, of density 4.19 at 18° C.

The phosphides, Ni₅P₂ and Ni₃P, have been described. The former of these exists in two modifications, namely, βNi₅P₂, which is stable at high temperatures and is transformed at 1025° C. into αNi₅P₂.