Anisotropy of linear expansion of CdGa2Se4

Heat expansion of CdGa2Se4 poly- and single crystals along the growth axis and normally to it has been studied. Both X-ray analysis and metallography have shown that the compound consists of one phase. The unit cell parameters have been calculated from the X-ray pictures as a=5.70 A and c=10.71 A. The heat expansion has been studied in the 300-873 K temperature range. The observed temperature dependence of linear expansion suggests that the CdGa2Se4 linear expansion coefficient is highly anisotropic. The coefficient of anisotropy of isothermal compressibility in two directions has been calculated. It indicates that along the growth axis of crystallization the repulsion between neighbouring molecules prevails over attraction