Rhodium complexes hexachloro

Beyond the 3+ oxidation state, rhodium forms a limited number of complexes in the 4+, 5+ and 6+ oxidation states. A recent review1221 gives an excellent summary of the chemistry of the higher oxidation state chemistry of Rh (as well as Ru, Os, Ir, Pd and Pt). For the 4+ oxidation state, the hexafluoro, hexachloro and trioxo dianions are well characterized. The known neutral species include RhF4 and some oxides. There are also scattered reports of Rhlv complexes containing substituted biguanides and Schiff base chelates. 

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