Materials Data on CsRb2SiF7 by Materials Project
CsRb2SiF7 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Cs1+ is bonded to six F1- atoms to form distorted CsF6 octahedra that share corners with four equivalent SiF6 octahedra and corners with six equivalent CsF6 octahedra. The corner-sharing octahedra tilt angles range from 0–68°. There are two shorter (2.98 Å) and four longer (3.15 Å) Cs–F bond lengths. Rb1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Rb–F bond distances ranging from 2.92–3.12 Å. Si4+ is bonded to six F1- atoms to form SiF6 octahedra that share corners with four equivalent CsF6 octahedra. The corner-sharing octahedral tilt angles are 68°. There is two shorter (1.72 Å) and four longer (1.73 Å) Si–F bond length. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to three equivalent Rb1+ and one Si4+ atom. In the second F1- site, F1- is bonded to two equivalent Cs1+ and four equivalent Rb1+ atoms to form corner-sharing FCs2Rb4 octahedra. The corner-sharing octahedra tilt angles range from 0–25°. In the third F1- site, F1- is bonded in a single-bond geometry to two equivalent Cs1+, two equivalent Rb1+, and one Si4+ atom.