MEASUREMENTS OF HIGH-TEMPERATURE HEAT-CONTENT OF THE II-VI AND IV-VI (II-ZN, CD IV-SN, PB VI-SE, TE) COMPOUNDS

High temperature heat contents of the II-VI and IV-VI compounds (II: Z n, Cd IV: Sn, Pb VI:Se, Te) were measured over the temperature range o f 700-1550 K using a drop calorimeter. The heat of alpha-beta transfor mation of SnSe was 1.1+/-0.1 kJ/mol at 788+/-2 K, and the heat of fusi on of CdSe, CdTe, SnSe, PbSe, SnTe and PbTe were 44.8+/-0.2, 43.5+/-0. 3, 35.5+/-0.4, 42.3+/-0.4, 39.5+/-0.3 and 47.6+/-0.4 kJ/mol, respectiv ely, at the corresponding melting points of 1521+/-3, 1373+/-3, 1149+/ -2, 1351+/-2, 1080+/-3 and 1209+/-2 K. The heat contents and heat capa city equations were derived using the Shomate function for the solid c ompounds and the least square method for liquid phases. Based on the t hird law method, the Gibbs free energies of formation were determined form the obtained heat capacity data.