Published online by Cambridge University Press: 04 September 2013
X-ray powder diffraction data, unit-cell parameters, and space group for potassium erbium fluoride, K0.5Er0.5F2, are reported [a = 5.6862(5) Å, unit-cell volume V = 183.85 Å3, Z = 4, and space group Fm-3m]. Potassium erbium fluoride is isostructural with a large family of fluorides represented by the mineral fluorite CaF2. All of the measured lines of the title compound were indexed and are consistent with the Fm-3m space group. No detectable impurities were observed.