 This stabilisation of higher oxidation states became significant in the Nyholm-Rail reaction where the ditertiary arsine, diars undergoes a condensation reaction to a tritertiary arsine, triars.Nyholm prepared examples of divalent octahedral complexes of the type M(diars)2X2, where X is Cl, Br or I, and M is Cr, Mn, Fe, Co, Ni, Mo, Tc, Ru, Pd, W, Re, Os, and Pt.Many of these divalent complexes are sensitive to aerial oxidation.