“…Such compounds have previously attracted attention because of interest in the magnetic, electrical, catalytic and gas sensing properties of the systems. In contrast, the more limited attention to tindoped a-Cr 2 O 3 phases appears to have been focused on their surface properties [6][7][8]. Although there have been several studies of the a-Fe 2Àx Cr x O 3 [9 -11] system there appears to have been little activity in the doping of these materials by tin.…”