ELECTRONIC-STRUCTURE OF BASN1-XSBXO3, FOR 0.0 LESS-THAN-OR-EQUAL-TO 0.2

The Mossbauer effect of the 37.2 keV transition of Sb-121 and the 23.88 keV gamma-transition of Sn-119 has been employed to study the electronic configuration of Sb and Sn ions in the conducting materials BaSn1-xSbxO3 for 0 less-than-or-equal-to x less-than-or-equal-to 0.2. A single-resonance absorption line is observed for each isotope. The isomer shifts change slightly with Sb content and fall in the region corresponding to Sb(V) and Sn(IV) valence states, respectively. The Sb isomer shift (IS) of 7.5 mm/s is significantly depressed (approximately 1 mm/s) relative to its value in a typical Sb(V)O6 chromophore and indicates a high degree of covalency, corresponding to significant 5s(m)5p(n) hybridization. The Sn IS of 0.1 mm/s indicates that the Sn atoms in BaSn1-xSbxO3 are more covalent than in BaSnO3. Charge disproportionation of the Sn and Sb into Sn(II) and Sn(IV) or Sb(III) and Sb(V) has not been observed.