The anion-excess fluorite-like solid solutions with general composition Bi_1−<i>x</i>Te_<i>x</i>(O,F)_2+<i>δ</i> (<i>x</i> > 0.5) have been synthesized by a solid state reaction of TeO₂, BiF₃ and Bi₂O₃ at 873 K with following quenching. The homogeneity areas and polymorphism of the I ↔ IV Bi_1−<i>x</i>Te_<i>x</i>(O,F)_2+<i>δ</i> phases were investigated. The crystal structure of the low temperature IV-Bi_1−<i>x</i>Te_<i>x</i>(O,F)_2+<i>δ</i> phase has been solved using electron diffraction and X-ray powder diffraction (<i>a</i> = 11.53051(9) Å, S.G. <i>Ia</i>-3, <i>R</i>_I = 0.046, <i>R</i>_P = 0.041). Glass formation area in the Bi₂O₃-BiF₃-TeO₂ (10% TiO₂) system was investigated. IVBi_1−<i>x</i>Te_<i>x</i>(O,F)_2+<i>δ</i> phase starts to crystallize at short-time (0.5-3 h) annealing of oxyfluoride glasses at temperatures above <i>T</i>_g (600-615 K). The ionic conductivity of the crystalline Bi_1−<i>x</i>Te_<i>x</i>(O,F)_2+<i>δ</i> phase and corresponding glass-ceramics was investigated. Activation energy of conductivity <i>E</i>_a = 0.41(2) eV for the IV-Bi_1−<i>x</i>Te_<i>x</i>(O,F)_2+<i>δ</i> crystalline samples and <i>E</i>_a = 0.73 eV for the glass-ceramic samples were obtained. Investigation of the oxyfluoride samples with a constant cation ratio demonstrates essential influence of excess fluorine anions on the ionic conductivity.< Leer menos