Comment
Figure shows only the first heating process. Sulfidation reaction starts at 245�Ž, and finishes at 525�Ž. Exothermic broad peak, at 362�Ž, corresponding to ƒ¢Hr=875.5J/g. Next, phase transition of Ni3S2
at 543�Ž�@ƒ¢Htr=147.4J/g, at 639�Ž�@ƒ¢Htr=11.6J/g.
The enthalpy of formation
�@Product is the trigonal Ni3S2.
ĢHf=50.2Kcal/mol.