Materials Data on K2MgF4 by Materials Project
K2MgF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of K–F bond distances ranging from 2.67–2.85 Å. Mg2+ is bonded to six F1- atoms to form corner-sharing MgF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.02 Å) and two longer (2.03 Å) Mg–F bond lengths. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to five equivalent K1+ and one Mg2+ atom to form a mixture of distorted corner and edge-sharing FK5Mg octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second F1- site, F1- is bonded in a distorted linear geometry to four equivalent K1+ and two equivalent Mg2+ atoms.