X-ray studies on the thermal expansion of tellurium dioxide

Abstract

Using a Unicam 19 cm high temperature powder camera, the precision lattice parameters of tellurium dioxide have been determined at different temperatures in the range 30 to 461 °C. Using this data, the coefficients of thermal expansion, α∥ and α⊥ parallel and perpendicular to the principal axis respectively, have been evaluated. The temperature dependence of the coefficients of thermal expansion is represented by the following equations: α∥=29.673×10−6+1.552sx10−8T+1.069sx10−10T2 α⊥=9.875sx10−6−5.440sx10−9T+4.572sx 10−12 T2 HereT is the temperature in °C. The thermal expansion of tellurium dioxide has been explained in terms of the interionic distances.