oxyfluoridetype

Oxyfluoridetype is a provisional, informal designation used in some discussions of inorganic chemistry to refer to compounds that integrate oxide and fluoride anions within a single crystal lattice. The term is not widely standardized in the literature, but it is used to describe mixed-anion materials whose framework accommodates both O2− and F− and where the two anion types influence physical properties differently than pure oxides or fluorides.

Structurally, oxyfluoride materials typically feature distinct sites for oxide and fluoride in a shared cation framework. They often adopt fluorite- or perovskite-related structures and can exhibit anion ordering, site-selective substitution, or layered motifs. The mixed anion composition affects lattice energy, bonding, and electronic structure, enabling properties such as altered band gaps and tunable luminescence, as well as potential improvements in ionic conductivity compared to single-anion analogs.

Synthesis commonly proceeds by high-temperature solid-state reactions, sometimes with fluoride sources or fluxes, and by procedures that promote controlled anion exchange or partial substitution. Doping with lanthanide ions (for example Eu, Er, or Yb) yields phosphor materials with characteristic red to green emission or upconversion behavior.

Representative examples cited in some sources include yttrium oxyfluoride YOF and lanthanum oxyfluoride LaOF, along with related rare-earth oxyfluorides. In practice, researchers more frequently describe these materials as oxyfluorides or mixed-anion oxides and fluorides rather than using a separate "oxyfluoridetype" category; the terminology varies by author and context.