Formation of cadmium sulfide on thermolysis of thiourea interaction products with cadmium chloride

Using the methods of chemical analysis, IR-spectroscopy and X-ray diffraction phase analysis, products of interaction between solutions of CdCl2 and SC(NH2)2 at different mole ratios have been studied. The character of interaction and thermal stability of complex salts formed are considered to clarify regularities, determining the properties of CdS films, prepared by pulverization method. It is established, that independent of mole ratios of the initial components CdCl2:Sc(NH2)2 in the range 1:1-1:6, complex compound [Cd(SCN2H4)2]Cl with ligand coordination via sulphur atom is formed. Investigations, carried out using the methods of TG, DTG and DTA, have shown, that at 240-250 deg C a stepped destruction of the complex [Cd(SCN2H4)2]Cl2 with the formation at the first stage of the complex [Cd(SCN2H4)]Cl2 and decomposition of liberated SC(NH2)2 into gaseous products take place. Further thermal decomposition of the complex takes place with the formation of CdS and it ends at 400 deg C. Air oxygen promotes a more complete decomposition of organic constituents, however, it causes formation of CdSO4 impurity