Nickel Sesquiselenide, Ni₂Se₃

Nickel Sesquiselenide, Ni₂Se₃, is obtained by exposing anhydrous nickel chloride to hydrogen selenide at dull red heat. Nickelo-nickelic Selenide, Ni₃Se₄, is obtained in the same way as a grey product apparently crystallising in the cubic system. The Diselenide, NiSe₂, is a dark grey compound obtained by heating anhydrous nickel chloride in hydrogen selenide at 300° C.