Materials Data on Cs2CaBr4 by Materials Project
Cs2CaBr4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs1+ is bonded in a 9-coordinate geometry to nine Br1- atoms. There are a spread of Cs–Br bond distances ranging from 3.60–4.07 Å. Ca2+ is bonded to six Br1- atoms to form corner-sharing CaBr6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.87 Å) and two longer (2.90 Å) Ca–Br bond lengths. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded to four equivalent Cs1+ and two equivalent Ca2+ atoms to form a mixture of distorted face, edge, and corner-sharing BrCs4Ca2 octahedra. The corner-sharing octahedra tilt angles range from 0–55°. In the second Br1- site, Br1- is bonded to five equivalent Cs1+ and one Ca2+ atom to form distorted BrCs5Ca octahedra that share corners with seventeen BrCs4Ca2 octahedra, edges with eight equivalent BrCs5Ca octahedra, and faces with four equivalent BrCs4Ca2 octahedra. The corner-sharing octahedra tilt angles range from 0–55°.