Materials Data on KSr2I5 by Materials Project

KSr2I5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight I1- atoms. There are a spread of K–I bond distances ranging from 3.50–4.11 Å. There are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight I1- atoms. There are a spread of Sr–I bond distances ranging from 3.40–3.64 Å. In the second Sr2+ site, Sr2+ is bonded to seven I1- atoms to form distorted edge-sharing SrI7 pentagonal bipyramids. There are a spread of Sr–I bond distances ranging from 3.26–3.49 Å. There are five inequivalent I1- sites. In the first I1- site, I1- is bonded to two equivalent K1+ and two equivalent Sr2+ atoms to form distorted IK2Sr2 trigonal pyramids that share corners with six IK2Sr3 square pyramids, corners with two equivalent IK2Sr2 trigonal pyramids, edges with three IK2Sr3 square pyramids, and an edgeedge with one IK2Sr2 trigonal pyramid. In the second I1- site, I1- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Sr2+ atoms. In the third I1- site, I1- is bonded to two equivalent K1+ and three Sr2+ atoms to form distorted IK2Sr3 square pyramids that share corners with eight IK2Sr3 square pyramids, corners with two equivalent IK2Sr2 trigonal pyramids, an edgeedge with one IK2Sr3 square pyramid, edges with two equivalent IK2Sr2 trigonal pyramids, and a faceface with one IK2Sr3 square pyramid. In the fourth I1- site, I1- is bonded to two equivalent K1+ and three Sr2+ atoms to form distorted IK2Sr3 square pyramids that share corners with four equivalent IK2Sr3 square pyramids, corners with four equivalent IK2Sr2 trigonal pyramids, edges with three IK2Sr3 square pyramids, an edgeedge with one IK2Sr2 trigonal pyramid, and a faceface with one IK2Sr3 square pyramid. In the fifth I1- site, I1- is bonded in a distorted rectangular see-saw-like geometry to four Sr2+ atoms.