A new mixed valence compound of vanadium

A new mixed valence compound of vanadium was prepared in nonpolar solvents by mixing vanadyl(IV) bis(acetylacetonate) with a similar copper(II) or zinc complex and with a tetraalkylammonium salt. Based upon a variety of physical studies, the proposed formula for the deep violet crystals obtained is [(C2H5)4N]4[V10O28H4] in which eight of the vanadium atoms are in the quinquivalent state and two are in the quadrivalent state. The optical spectrum exhibits a very broad and intense band at about 20,000 cm−1 as well as a less intense but very broad band centered about 12,100 cm−1. The ESR spectrum shows a hyperfine splitting by two equivalent 51V nuclei. An attempt to assign these spectra is made.