Mechanochemical syntheses of perovskite KMIIF3 with cubic structure (MuII = Mg, Ca, Mn, Fe, Co, Ni, and Zn)

An equi-molar mixture of potassium fluoride (KF) and one of alkaline-earth or transition metal fluoride (MF2)-F-II (M-II = Mg, Ca, Mn, Fe, Co, Ni, and Zn) was ground in air by using a planetary ball mill to investigate mechanochemical (MC) synthesis of fluoroperovskites (KMF3)-F-II. Rietveld refinement for the ground mixtures was conducted on the basis of XRD data to inquire into structural properties of the (KMF3)-F-II synthesized mechanochemically. The synthesis reactions proceed with grinding time, and ultimately a single phase of cubic structural (KMF3)-F-II (Pm3m, Z = 1) was obtained after grinding for 21.6ks. The values of unit cell parameter, alpha, of (KMF3)-F-II synthesized by MC reaction, are slightly larger than those by solid-state reaction at high temperature, and this may be attributed to structural distortions caused by intensive grinding.