The Crystal Structure of TlP5.

Abstract

The crystal structures of the semiconductor Tiz03 and the semimetal (Ti0.900V0.100)203 were determined from X-ray diffraction data collected from single crystals. The compounds are isostructural with A1203 of rhombohedral unit cell dimensions of a = 5.4325(g) A and a = 56.75(l) " for Ti203, and a = 5.4692(g) 8, and a = 55.63(l) " for the doped system. The effect of substitution of V +3 is to increase the metal-metal distance across the shared octahedral face from 2.579 A in Tiz03 to 2.658 A in (Ti,,.sooVo.Ioo)zO~, while decreasing the metal-metal distance across the shared octahedral edge from 2.997 to 2.968 A. The metal-oxygen distances exhibit only small changes. These structural changes are consistent with the band theory proposed by Van Zandt, Honig, and Goodenough (9) to explain changes in electrical and other properties with increasing vanadium content in (Tir-,V,),O,.