Fluorideoxygen

Fluorideoxygen, commonly referred to in the literature as oxyfluoride, denotes compounds that contain both fluoride and oxide anions in the same solid. These materials span a range of structures, from layered oxides with intercalated fluoride ions to mixed-anion frameworks in which fluorine substitutes for oxide in a perovskite-like lattice. Representative examples include lanthanum oxyfluoride LaOF and bismuth oxyfluoride BiOF, as well as a variety of rare-earth and transition-metal oxyfluorides.

Synthesis of oxyfluorides typically involves incorporation of fluoride into oxide precursors. Methods include solid-state fluorination or fluorination of oxides with fluoride sources such as ammonium fluoride, hydrogen fluoride, or metal fluorides, often under controlled atmospheres and temperatures. Hydrothermal or solvothermal routes can also yield oxyfluorides, sometimes enabling tailored anion ordering. Topotactic fluorination of oxide precursors allows partial replacement of oxide by fluoride while preserving the overall cation framework.

Properties of fluoride-oxide compounds arise from their mixed anion chemistry. They often exhibit structural flexibility, wide band gaps, and, when doped with rare-earth ions, notable luminescent properties. Some oxyfluorides can support fluoride-ion conduction at elevated temperatures, making them of interest as solid-state electrolytes. The exact properties depend on composition, cation size, and the degree of fluoride incorporation, with lattice parameters and defect chemistry tunable through synthesis.

Applications include phosphors for lighting and scintillators, transparent ceramics and optical coatings, and, in some cases, materials for fluoride-ion batteries or catalytic systems. Safety concerns center on handling fluorinating reagents, which can be corrosive and toxic. The term fluorideoxygen is not uniformly standardized; oxyfluoride and fluoride oxide are more commonly used descriptors in the literature.