Volumetric effects of ZnTe, CdTe and HgTe compounds at melting and subsequent heating

The temperature dependence of the density of CdTe, ZnTe and HgTe compounds was studied by means of the gamma - ray attenuation method both in solid an d liquid states. A decrease in the density in the course of the crystal --> melt phase transition and subsequent heating for ZnTe and CdTe is obtained . The volume effect during the HgTe melting is negative. According to our e valuations, the increase of the external pressure should result in an incre ase of the fusion temperature for ZnTe and CdTe. The dT/dP coefficient of t he HgTe at the melting point is negative. The density of the molten HgTb co mpound changes along a curve with a maximum. This anomaly is explained by t he thermal dissociation of the HgTe with the formation of 2 complex associa tes in the liquid phase. The thermal expansion of the Zn and Cd tellurides is considered on the basis of the characteristics of the interatomic bonds strength.