black powder(s); trig, yellow metallic luster; enthalpy of fusion 30.10 kJ/mol; can be formed by fusing Ni powder(s) and molten sulfur; other sulfides include Ni2S, 12137-08-5, Ni3S2, 12035-72-2 (heazlewoodite), NiS2, 12035-51-7, and Ni3S, 12137-12-1 (polydymite) [KIR81] [STR93] [CRC10] [JAN85]
The black nickel sulphide precipitated from nickel(II) salt solutions
by ammonium sulphide in neutral but not strongly acid solution is the so-called α-NiS ; it
consists largely of amorphous Ni(SH,OH)2 when first precipitated. At low pH this crystallizes
to give mainly the rhombohedral γ-NiS, while at higher pH the hexagonal β-NiS(Ni1-XS) crystallizes.
