Sn-119 Mossbauer study of cassiterite-rutile solid solutions, (Sn1-xTix)O-2

Single phase rutile-cassiterite solid solutions (Sn1-xTix)O-2 with x = 0.00 , 0.15, 0.30, 0.47, 0.70, 0.90, 0.99, 1.00 were synthesized above the solvu s temperatures in the system SnO2-TiO2, cassiterrite-rutile, from coprecipi tates obtained by hydrolysis of the respective (l-x) SnCl4 x TiCl4 mixtures . The samples were studied by TEM, XRD and Sn-119 MS. The isomer shift in M ossbauer spectra of Sn-119 increases almost linearly with increasing x. Thi s effect, due to increasing s-electron density at the tin nuclei, is interp reted as an increase of O 2p - Sn 5s overlap caused by the reduction of the average M-O-6 distance with increasing x. The quadrupole splitting shows s trong positive deviation from linearity, decreasing from the pure SnO2 to T iO2, doped with 1 mole % of (SnO2)-Sn-119.