  To compare the metal-insulator transitions (MITs) of VO2 and V2O3 we analyze
the relations between the structural and electronic properties of the vanadium
Magneli phases. These materials set up the homologous series VnO(2n-1) (3 <= n
<= 9) and have crystal structures comprising typical dioxide-like and
sesquioxide-like regions. As the MITs of the vanadium Magneli phases are
accompanied by structural transformations, we are able to discuss the effects
of characteristic changes in the local atomic environments. The systematic
investigation of the transport properties is based on a new and unifying
description of the crystal structures of the Magneli phases including VO2 and
V2O3. Our results lead to a comprehensive understanding of the MITs in the
Magneli class and shed new light on the role of particular electronic states
for the MIT of V2O3.
