Pervanadyl

Pervanadyl (VO2+) is a pale yellow oxycation of vanadium(V). It is the predominant vanadium(V) species in acidic solutions with pH between 0 and 2, and its salts are formed by protonation of vanadium(V) oxide in such solutions:
 * V2O5 + 2 H+ -> 2 VO2+ + H2O (K = $0.034$)

The ion can form a complex with a single aminopolycarboxylate ligand, or with tridentate Schiff base ligands.

The VO2+/VO(2+) redox couple is used at the cathode of the vanadium redox battery. The standard reduction potential of this couple is +1.00 V.