Novel Metal(II) Fluoridooxidomolybdates(VI)

Abstract

The synthetic and structural chemistry of inorganic fluoridomono-oxidomolybdates(VI) is not well explored. These compounds containing anions such as [Mo2O2F9]−, [MoOF5]−, and [MoOF6]2− form when a relatively weak Lewis acid MoOF4 reacts with fluoride-ion donors. Typically, MoOF4 is synthesized by controlled hydrolysis of MoF6 with SiO2 in anhydrous HF. In this work a different, more convenient route was investigated. The MoOF4 was prepared by solvolysis of commercially available MoOCl4 in anhydrous HF. Novel metal(II) fluoridooxidomolybdate(VI) salts were synthesized either by reacting the corresponding divalent fluorides, MF2, e.g. CaF2, SrF2, BaF2 or PbF2, with MoOF4 in anhydrous HF or by forming the Lewis acid in situ by solvolysis of MoOCl4 in anhydrous HF in the presence of MF2. The resulting air-sensitive compounds were characterized by vibrational spectroscopy (Raman and ATR-FTIR), powder X-ray diffraction, and low-temperature single-crystal X-ray diffraction.