Thermodynamic properties of K2TeO3 (s)

The thermodynamic properties of potassium tellurate was established by studying the heterogeneous equilibrium K2TeO3(s) = K2O(s) + TeO2(g) by transpiration technique using pure oxygen as carrier gas in the temperature range 1005 to 1145 K. The condensate was exclusively identified as TeO2(s) by XRD and chemical analysis. Residue left in the alumina boat after the transpiration experiment was identified as K2O by XRD, which confirmed the co-existence of K2O(s) with K2TeO3 (s). The vapour pressure of TeO2 (g) over pure K2TeO3 (s) was calculated and is given by, logp (TeO2)/Pa ± 0.0143= - 5187.04/T (K)+ 5.2869. Using the experimental data the ΔfGK2TeO3(s) was calculated and can be given by, ΔfG (K2TeO3 s,T) kJ/mol ± 0.0032=-783.35 + 0.4727T (K). (author)