Materials Data on KNaMg2F6 by Materials Project

Abstract

KNaMg2F6 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. K1+ is bonded to twelve equivalent F1- atoms to form KF12 cuboctahedra that share corners with twelve equivalent KF12 cuboctahedra, faces with six equivalent NaF12 cuboctahedra, and faces with eight equivalent MgF6 octahedra. All K–F bond lengths are 2.83 Å. Na1+ is bonded to twelve equivalent F1- atoms to form NaF12 cuboctahedra that share corners with twelve equivalent NaF12 cuboctahedra, faces with six equivalent KF12 cuboctahedra, and faces with eight equivalent MgF6 octahedra. All Na–F bond lengths are 2.83 Å. Mg2+ is bonded to six equivalent F1- atoms to form MgF6 octahedra that share corners with six equivalent MgF6 octahedra, faces with four equivalent KF12 cuboctahedra, and faces with four equivalent NaF12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Mg–F bond lengths are 2.00 Å. F1- is bonded in a distorted linear geometry to two equivalent K1+, two equivalent Na1+, and two equivalent Mg2+ atoms.