Schematic representation of a slightly oxidized redox couple for different positions relative to the top of the anionpbands. (a) Itinerant versus polaronic character of hole states of a couple on the approach to the top of the anionpband, (b) pinned couple with predominantly antibonding (a.b.) anionphole states and predominantly cationd bonding (b.) states, and (c) couple too far below top of anionpband for significant cationdcharacter in hole states.^[44]