Molybdohypophosphites

A solution containing sodium hypophosphite (1 molecule), sodium molybdate (4 molecules), and hydrochloric acid (7 molecules) gives, with ammonium chloride, white needles of the salt NH₄[H₂P(Mo₂O₇)₂]6H₂O. The corresponding potassium and guanidinium salts have been prepared, but contained admixed trimolybdate.

The halogen compounds, MoCl₅.POCl₃; MoCl₅.PCl₅; MoCl₄.PCl₅ and MoCl₄.2PCl₅; and Mo₃Br₄(PO₄H₂)₂, have been described.