A torsion-effusion study on the sublimation of Cu2Te

The sublimation of Cu2Te was studied and its vapor pressure was measured by the torsion method. In the covered temperature range, the temperature dependence of the total vapor pressure can be expressed by the following equation: logp (kPa)=(6.17+-0.20)-(11680+-300) (K /T) (1084-1234 K). The sublimation process of Cu2Te is incongruent, and Te(g) and Te2(g) being the only gaseous species present in the vapor, the partial sublimation reactions were studied: Cu2Te(s) -> 2Cu(s) + Te(g), 2Cu2Te(s) -> 4Cu(s)+ Te2 (g). The standard sublimation enthalpies of these reactions, DH°(298 K) = 254+-10 and 248 +- 8 kJ, respectively, were derived by the second- and third-law treatment of the pressure data. The heat of formation of Cu2Te, DH°(.298 K)= -43 +- 6 kJ mol-1, was also derived.