TIN-INDIUM SULFIDE SPINELS - X-RAY STUDY AND EVIDENCE OF TIN MIXED-VALENCE FROM SN-119 MOSSBAUER-SPECTROSCOPY

The study of the In2S3-SnS-SnS2 system has allowed to highlight a wide solid solution range based on the cubic alpha-In2S3 vacant spinel structure. The general formula (In, square)8 [In, Sn(II), Sn(IV)]16S32 illustrates the occupancy of tetrahedral sites by indium and vacancies, and octahedral sites by indium and mixed-valence tin atoms. From X-ray powder diffraction data the evolution of the cubic cell parameters with the composition is discussed. Sn-119 Mossbauer effect measurements have been performed on the molar composition 80% In2S3 - 10 % SnS - 10 % SnS2 over the temperature range 80 K less-than-or-equal-to T less-than-or-equal-to 300 K. The lattice parameters have been determined. The recoilless fractions f (Sn(IV), 80 K) = 0.71 and f (Sn(II), 80 K) = 0.61 are discussed and compared with those of other tin compounds.