for
which the corresponding endothermic peak at 267 C was
obtained. The second peak at 286 C shows a weight gain
(10.24%) which may be due to adsorption of nitrogen by CuS and
Cu2S, and the final weight loss of 10.12% at 784 C indicates
desorption of nitrogen. After 784 C, the residue of 35.38% left corresponds
to 2CuS + 2Cu2S, for which corresponding endo and exothermic
peaks in the DTA at 329 and 431 C were obtained (Fig. 1).
The results of the thermal decomposition of the complex can be
explained on the basis of two types of coordination environment
adopted by the copper atoms. Looking at the structure of the complex
(Fig. 4) it can be seen that four copper atoms, which have a
coordination number of four, lose four ligand moieties without sulfur,
whereas the other two copper atoms, having a coordination
number of five, lose two complete ligand moieties along with sulfur,
leading to the formation of a mixture of 2Cu2S + 2CuS.