X-ray diffraction and Rietveld structural refinement of selected fluoroperovskites

Abstract

This study presents an X-ray diffraction analysis and Rietveld structural refinement of selected synthetic fluoroperovskite-type compounds including the Na1-xKxMgF3 solid solution series in addition to synthetic analogues of cryolite (Na2NaAlF6) and simmonsite (Na2LiAlF6). The Na1-xKxMgF3 solid solution series is comprised of three structurally distinct perovskite phases. In order of increasing potassium they are; orthorhombic (Pbnm, a = 5.3609(1), b = 5.4862(1), c = 7.6661(1), Z = 4) in the x = 0 - 0.35 compositional range, tetragonal (P4/mbm, a = 5.444(3), c = 3.9217(3), Z = 2) in the x = 0.40 ~ 0.46 compositional range and cubic (see document)