The vanadium Magnéli phases V_nO_2n-1

To compare the metal-insulator transitions (MITs) of VO₂ and V₂O₃ we analyze the relations between the structural and electronic properties of the vanadium Magnéli phases. These materials set up the homologous series V_nO_2n-1 (3 ≤ n ≤ 9) and have crystal structures comprising typical dioxide-like and sesquioxide-like regions. As the MITs of the vanadium Magnéli 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 Magnéli phases including VO₂ and V ₂O₃. Our results lead to a comprehensive understanding of the MITs in the Magnéli class and shed new light on the role of particular electronic states for the MIT of V₂O₃.