Materials Data on Rb2FeF4 by Materials Project
Rb2FeF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Rb–F bond distances ranging from 2.83–3.05 Å. Fe2+ is bonded to six F1- atoms to form corner-sharing FeF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.06 Å) and four longer (2.16 Å) Fe–F bond lengths. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to four equivalent Rb1+ and two equivalent Fe2+ atoms to form a mixture of distorted face, edge, and corner-sharing FRb4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 0–58°. In the second F1- site, F1- is bonded to five equivalent Rb1+ and one Fe2+ atom to form distorted FRb5Fe octahedra that share corners with seventeen FRb4Fe2 octahedra, edges with eight equivalent FRb5Fe octahedra, and faces with four equivalent FRb4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 0–58°.