¹¹⁹Sn Mössbauer study of the influence of a gas atmosphere on the valence state and distribution of tin atoms in the MgO structure

Abstract

Analysis of the Mössbauer spectra of dopant ¹¹⁹Sn in cubic MgO has demonstrated that the Sn²⁺ ions can be stabilized on the surface of crystallites of an oxide with a structure differing from the corundum structure. The Mössbauer parameters (at 100 K, the isomer shift is δ = 2.50 ± 0.01 mm/s and the quadrupole splitting is Δ = 2.30 ± 0.02 mm/s) point to the stereochemical activity of the lone pair of Sn²⁺. Being in contact with oxygen at 295 K, tin is rapidly converted to the tetravalent state (δ = 0.08 ± 0.01 mms, Δ = 0.58 ± 0.01 mm/s). The lack of formation of Sn²⁺ on the surface of another cubic oxide (MnO) can be explained by rapid segregation of tin from the bulk of crystallites as stannate clusters.