Two bismuth oxyfluorides, BiOF and BiO 0.5F 2, have been prepared by soft chemistry. These two compounds are of interest for application as new type of positive electrode active materials in secondary lithium battery. BiOF was obtained directly from the fluorination of Bi 2O 3 by a saturated aqueous solution of NH 4F. BiO 0.5F 2 was obtained by the hydrolysis of β-NH 4BiF 4 at 70°C. The ammonium bismuth fluoride β-NH 4BiF 4, which is a new orthorhombic form of NH 4BiF 4, was obtained by reacting BiF 3 in a saturated aqueous solution of NH 4F. Two other ammonium bismuth fluorides, (NH 4) 0.5BiF 3.5 and NH 4Bi 3F 10, were also prepared by annealing β-NH 4BiF 4 at a relatively low temperature under inert atmosphere. The existence of the fluorite (NH 4) 0.5BiF 3.5 is reported for the first time in this paper.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry