STRUCTURE, IONIC CONDUCTION AND THERMODYNAMICS OF NEW COMPOUNDS BASED ON BISMUTH AND RENIUM OXIDES

Read more New compounds Bi₁₄ReO_24.5, Bi_12.5Lu_1.5ReO_24.5, Bi_12.5Ho_1.5ReO_24.5 were synthesized by solid-state method with bismuth oxide, Bi₂O₃, ammonium perrhenate, NH₄ReO₄, lutecium oxide, Lu₂O₃, and holmium oxide, Ho₂O₃. The lattice parameters and space group were determined by X-ray diffraction spectroscopy. Bi₁₄ReO_24.5 has tetrahedral symmetry, space group I 4/m, Bi_12.5Ho_1.5ReO_24.5 и Bi_12.5Lu_1.5ReO_24.5 have cubic symmetry, space group Fm3m. Ionic conduction of Bi12.5Lu1.5ReO24.5 phase was measured by impedance spectroscopy in a temperature range from 500 to 900 °C. It was shown Bi_12.5Ln_12.5ReO_24.5 is one of the best ionic conductors in range of medium temperatures and has the same conductivity as that for BiCuVO_x, Bi_12.5Ln_12.5ReO_24.5 (Ln = La, Nd) at 800 K. The heat of solution for Bi_12.5Lu_1.5ReO_24.5 was measured by solution calorimetry in hydrochloric acid with concentration 2 mol*L^-1 (2M). The heat of formation from binary oxides was estimated using finding and literary data; it was shown Bi_12.5Lu_1.5ReO_24.5 is thermodynamically stable at room temperatures.

Keywords:
bismuth oxide, Bi₂O₃, solution calorimetry, stability.
УДК 541.11 + 541.123 + 541.6

STRUCTURE, IONIC CONDUCTION AND THERMODYNAMICS OF NEW COMPOUNDS BASED ON BISMUTH AND RENIUM OXIDES