Yttrium oxyfluoride is an inorganic chemical compound with the formula . Under normal conditions, the compound is a colorless solid.
Yttrium oxyfluoride may be formed in the decomposition of crystalline hydrate of yttrium fluoride upon heating to 900 ðC in a vacuum:
Yttrium oxyfluoride can also be made by hydrolysis of yttrium fluoride with superheated steam at 800 ðC:
Yttrium oxyfluoride forms colorless crystals of tetragonal crystal system; its cell parameters are: a = 0.3910 nm, c = 0.5431 nm. According to hexagonal crystal family, the cell parameters are: a = 0.38727 nm, c = 1.897 nm, Z = 6.
Stable yttrium oxyfluoride material is used for inner walls of plasma process equipment.