polyoxovanadates

Polyoxovanadates are a subset of polyoxometalates consisting of vanadium–oxygen clusters that exist as discrete anions or neutral molecular species in aqueous solutions. Vanadium centers are predominantly in the +5 oxidation state, but mixed-valence VIV/VV species are common, endowing these clusters with rich redox chemistry and potential as redox mediators.

The structural landscape of polyoxovanadates is diverse. Well-known families include small Lindqvist-type clusters such as [V6O19]n− and larger assemblies like decavanadate [V10O28]6−, as well as lacunary and heterometal-containing derivatives. Structures often exhibit rich geometry, from ball-like cages to ring- or chain-like motifs, and can be tuned by pH, counterions, and substitution of other metals such as Nb, Mo, or W.

In solution, polyoxovanadates show multiple reversible redox couples and characteristic electronic spectra. Their redox activity underpins catalytic applications, including oxidation of organic substrates and, in some systems, water oxidation under electrochemical or photoelectrochemical conditions. They have also been explored as components in energy storage materials and in sensing platforms, where their redox properties enable signal generation or catalysis.

Research continues to expand the catalog of polyoxovanadates and to understand how structure governs reactivity, with emphasis on stabilizing higher nuclearity clusters, designing heterometallic derivatives, and integrating these species into materials and devices.

See also polyoxometalates, vanadates, redox catalysis.