(super 119) Sn Moessbauer study of cassiterite-rutile solid solutions, (Sn (sub 1-x) Ti (sub x) )O (sub 2)

Single-phase rutile-cassiterite solid solutions (Sn (sub 1-x) Ti (sub x) )O (sub 2) with x = 0.00, 0.15, 0.30, 0.47, 0.70, 0.90, 0.99 and 1.00 were synthesized above the solvus T in the system SnO (sub 2) -TiO (sub 2) from coprecipitates from the hydrolysis of the respective (1-x)SnCl (sub 4x) .TiCl (sub 4) mixtures, and studied by TEM, XRD and (super 119) Sn MS. The isomer shift in Moessbauer spectra of (super 119) Sn increases almost linearly with increasing x. This effect, due to increasing s-electron density as the tin nuclei, is interpreted as an increase of O 2p-Sn 5s overlap caused by the reduction of the average M-O (sub 6) distance with increasing x. The quadrupole splitting shows strong positive deviation from linearity, decreasing from pure SnO (sub 2) to TiO (sub 2) , doped with 1 mole % of (super 119) SnO (sub 2) .