The preparation of halogenotrimolybdate(II) compounds

Abstract

The preparation of halogenotrimolybdate(II) compounds containing the staphylonuclear groups, (Mo₃Cl₁₃)^7-, (Mo₃Br₁₃)^7-, (Mo₃Cl₁₂)^6-,(Mo₃Cl₁₁)^5-, (Mo₃Br₁₁)⁵-, (Mo₃Br₁₁)⁵- has been thoroughly examined and 11 new compounds are reported. No iodomolybdate(II) compounds were observed. When (NH₄)₇Mo₃Cl₁₃,H₂O is heated in vacuum, ammonium chloride is evolved but the final product is never MoCl₂. This chloromolybdate(II) undergoes rapid reaction with refluxing acetic acid to give an approximately two-thirds yield of molybdenum(II) acetate. This suggests the cleaving of an Mo₃ group to give Mo₂(CH₃CO₂)₄. Crystalline [Co en₃]₃Mo₃Cl₁₅,₆H₂O undergoes spontaneous intramolecular redox reaction which is stimulated by light, or moisture, but not oxygen.