Peroxide is a common ligand in metal complexes. Within the area of transition metal dioxygen complexes, functions as a bidentate ligand. Some complexes have only peroxide ligands, for example, chromium(VI) oxide peroxide (). Similarly, molybdate reacts in alkaline media with peroxide to form red peroxomolybdate . The reaction of hydrogen peroxide with aqueous titanium(IV) gives a brightly colored peroxy complex that is a useful test for titanium as well as hydrogen peroxide. Many transition metal dioxygen complexes are best described as adducts of peroxide.Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. .
