Tri-nickel Diarsenide, Ni₃As₂

Tri-nickel Diarsenide, Ni₃As₂, is formed by reducing nickel arsenate or a mixture of nickel oxide and arsenious oxide with potassium cyanide, and also when reduced nickel is heated at 800-1400° C. in vaporised arsenic chloride. It is a grey substance, which melts at 1000° C.; density 7.86. It is soluble in acids and fused alkalies.