Hydrolysis of ammonium oxofluorotungstates: A 19F, 17O and 183W NMR study

Abstract Fluorine-19 and natural abundance 17 O and 183 W NMR spectroscopy were employed for the characterization of aqueous solutions of (NH 4 ) 2 WO 2 F 4 and (NH 4 ) 3 WO 3 F 3 . Dissolution of the (NH 4 ) 2 WO 2 F 4 complex is accompanied by its partial acid hydrolysis to give the trans ( mer )-dimer, [W 2 O 5 F 6 ] 4− , and unreacted cis -[WO 2 F 4 ] 2− . The cis ( fac )-[W 2 O 5 F 6 ] 4− anion is the major soluble product resulting from the alkaline hydrolysis of (NH 4 ) 2 WO 2 F 4 along with the isolation of the solid (NH 4 ) 2 WO 3 F 2 . In addition, the edge-bridging dimer, [W 2 O 6 F 4 ] 4− , and the cyclic trimer, [W 3 O 9 F 6 ] 6− , are also suggested as hydrolysis products. Decomposition of (NH 4 ) 3 WO 3 F 3 occurs in aqueous solution to give NH 4 WO 3 F.