Standard Enthalpies of Formation of Te₂MoO₇ and ZnMoTeO₆

The tellurium, molybdenum, and zinc complex oxides Te₂MoO₇ and ZnTeMoO₆, promising starting materials for the preparation of zinc-containing tellurite–molybdate glasses, have been synthesized by heating accurately weighed amounts of orthotelluric acid and ammonium heptamolybdate and zinc nitrate crystal hydrates and identified by X-ray diffraction. Using reaction calorimetry, the standard enthalpies of formation of the complex oxides have been determined to be −1412.9 ± 23.7 and −1469.4 ± 23.2 kJ/mol, respectively. These values have been calculated as the difference between the standard enthalpies of solution of the complex oxides and mixtures of constituent binary oxides of corresponding content in concentrated hydrochloric acid and a concentrated sodium hydroxide solution.