On the Absence of Doubly Bonded Te═O Groups in TeO Glass.

Tellurium oxide clusters (TeO) were investigated through density functional theory to gain information on the structure of TeO glass. Among a large number of stable conformers studied, a cyclic, nonsymmetric structure was optimized without terminal Te═O double bonds. The dimer of this structure, (TeO), gives calculated Raman and infrared spectra in very good agreement with the experimental ones, with its total pair distribution function being also in agreement with results of neutron and high-energy X-ray diffraction studies. The (TeO) cluster consists mainly of TeO units connected by asymmetric and nearly symmetric Te-O-Te bridges as in γ-TeO and involves also edge-sharing through double-oxygen Te-O-Te bridges as in the β-TeO polymorph. The optimized cluster structure is slightly unstable compared to the calculated global minimum structure, suggesting a kinetically stable product similar to its corresponding experimental TeO glass.