Vanadyl ion explained

The vanadyl ion or oxovanadium(IV) cation, VO²⁺,^[1] is a functional group that is common in the coordination chemistry of vanadium. Complexes containing this functional group are characteristically blue or purple^[2] and paramagnetic.^[3] A triple bond is proposed to exist between the V⁴⁺ and O²⁻ centers.^[4] The description of the bonding in the vanadyl ion was central to the development of modern ligand-field theory.^[5]

Natural occurrence

Minerals

Cavansite and pentagonite are vanadyl-containing minerals.

Water

VO²⁺, often in an ionic pairing with sodium (NaH₂VO₄), is the second most abundant transition metal in seawater, with its concentration only being exceeded by molybdenum.^[6] In the ocean the average concentration is 30 nM. Some mineral water springs also contain the ion in high concentrations. For example, springs near Mount Fuji often contain as much as 54 μg per liter.

Vanadyl-containing compounds

Oxovanadium(IV)

• vanadyl acetylacetonate, VO(acac)₂
• vanadyl sulfate, VOSO₄
• vanadyl acetate, VO(CH₃COO)₂

Oxovanadium(V)

• vanadyl isopropoxide, VO(O-iPr)₃ (iPr denotes isopropyl)
• vanadyl nitrate, VO(NO₃)₃^[7]
• vanadyl perchlorate,
• vanadyl fluoride,
• vanadyl chloride,

Related species

• pervanadyl ion,,^[8] also known as the dioxovanadium(V) ion
• metavanadate ion,
• orthovanadate ion,
• thiovanadyl ion, VS²⁺
• titanyl ion, TiO²⁺
• niobyl ion, NbO²⁺
• tantalyl ion, TaO²⁺

Notes and References

1. Bertrand. Gary L.. Stapleton. George W.. Wulff. Clause A.. Hepler. Loren G.. Thermochemistry of Aqueous Pervanadyl and Vanadyl Ions. Inorg. Chem.. July 1966. 5. 7. 1283–1284. 10.1021/ic50041a048.
2. Bellhausen. C.J.. Gray. Harry B.. The Electronic Structure of the Vanadyl Ion. Inorganic Chemistry. 1. 1. 1962. 111-122. 10.1021/ic50001a022.
3. Smith. Thomas S. II. LoBrutto. Russell. Pecoraro. Vincent L.. Paramagnetic spectroscopy of vanadyl compounds and its applications to biological systems. Coordination Chemistry Reviews. 228. 1. 2002. 1-18. 10.1016/S0010-8545(01)00437-4. 12 November 2025. University of Delaware.
4. Gray, H. B. . Winkler, J. R. . Living with Oxygen. Accounts of Chemical Research. 2018. 51. 8. 1850–1857. 10.1021/acs.accounts.8b00245. 30016077. 6106048.
5. Ballhausen. C. J.. Gray. Harry B.. 1962-02-01. The Electronic Structure of the Vanadyl Ion. Inorganic Chemistry. 1. 1. 111–122. 10.1021/ic50001a022. 0020-1669. subscription.
6. Book: Rehder. Dieter. Bioinorganic Vanadium Chemistry. 2008. John Wiley & Sons, Ltd. Hamburg, Germany. 9780470065099. 5 & 9–10. 1st. 10.1002/9780470994429. Inorganic Chemistry.
7. Varetti. E.L.. Brandán. S.A.. Ben Altabef. A.. Vibrational and electronic spectra of vanadyl nitrate, VO(NO₃)₃. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. April 1995. 51. 4. 669–675. 10.1016/0584-8539(94)00154-4. 1995AcSpA..51..669B.
8. Satyanarayan. Pal. Kasiraman. Rinku Radhika. Mononuclear Pervanadyl Complexes with Tridentate Schiff Bases: Self-assembling via C–H…oxo and π-π Interactions. Zeitschrift für Anorganische und Allgemeine Chemie. July 2001. 627. 7. 1631–1637. 10.1002/1521-3749(200107)627:7<1631::AID-ZAAC1631>3.0.CO;2-H.