119SN MOSSBAUER STUDY OF CASSITERITE-RUTILE SOLID SOLUTIONS, (SN(1-X)TI(X))O2

Abstract

Single phase rutile-cassiterite solid solutions (Sn(1-x)Ti(x))O2 with x = 0.00, 0.15, 0.30, 0.47, 0.70, 0.90, 0.99, 1.00 were synthesized above the solvus temperatures in the system SnO2-TiO2, cassiterrite-rutile, from coprecipitates obtained by hydrolysis of the respective (1-x) SnCl4 xTiCl4 mixtures. The samples were studied by TEM, XRD and 119Sn MS. The isomer shift in Mossbauer spectra of 119Sn increases almost linearly with increasing x. This effect, due to increasing s-electron density at the tin nuclei, is interpreted as an increase of O 2p - Sn 5s overlap caused by the reduction of the average M-O6 distance with increasing x. The quadrupole splitting shows strong positive deviation from linearity, decreasing from the pure SnO2 to TiO2, doped with 1 mole % of 119SnO2.