INTERSTITIAL POSITIONS OF TIN IONS IN ALPHA-(FERICHSN)(2)O-3 SOLID-SOLUTIONS PREPARED BY MECHANICAL ALLOYING

The microstructure of samples of 91, 85, and 71 mol % alpha-Fe-2-O-3-S nO2. prepared by mechanical alloying, has been studied by x-ray diffra ction with Rietveld structure refinements, On the basis of the structu re refinements to the whole x-ray diffraction patterns for the four as -milled samples, it is found that tin ions do not substitute iron ions in the solid solution, although this model is generally assumed in th e literature. The Sn4+ ions occupy the empty octahedral holes in the l attice of the alpha-Fe2O3 phase.