Vanadium (V) solution. Image 1 of 4. Acidic aqueous solution of dioxovanadium (V) ions (VO2+), with bits of zinc metal. The vanadium is in its +5 (V) oxidation state, as shown by the yellow colour. Vanadium is a transistion metal, and, like many other transistion metals, its electronic structure can absorb light at a particular wavelength, giving rise to strongly coloured ions and complexes. The lower oxidation states of vanadium are prepared from the dioxovanadium ion by the addition of more acid and zinc to catalyse further reductions. See images A500/687-690 for all four oxidation states of vanadium.