Structural stability in the spinel compound CdIn2S4

Summary Experimental as well as theoretical investigations have been made about the detailed nature of the cation distribution in the spinel compound CdIn₂S₄. A microwave passive radiometry technique has been adopted to search for phase transitions in the temperature range 300 to 500 K. The experimental results are consistent with the specific-heat data obtained by Czaja and give further evidence for a second-order transition at 403 K. A recently developed semi-classical approximation has been used in order to obtain reliable structuraa energy values without introducing any adjustable parameter. Our theoretical result for the equilibrium lattice constant is very close to the experimental value. As for the cation distribution it appears that the distribution corresponding to the inverse phase is favoured in energy, atT=0 K, with respect to the normal one. Supported in part by M.P.I., Italia.