Materials Data on KSm2I5 by Materials Project

Abstract

KSm2I5 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 3.54–3.87 Å. There are two inequivalent Sm2+ sites. In the first Sm2+ site, Sm2+ is bonded in a 8-coordinate geometry to eight I1- atoms. There are a spread of Sm–I bond distances ranging from 3.21–3.54 Å. In the second Sm2+ site, Sm2+ is bonded to seven I1- atoms to form distorted edge-sharing SmI7 pentagonal bipyramids. There are a spread of Sm–I bond distances ranging from 3.17–3.36 Å. There are five inequivalent I1- sites. In the first I1- site, I1- is bonded to two equivalent K1+ and two equivalent Sm2+ atoms to form distorted IK2Sm2 tetrahedra that share corners with four equivalent IK2Sm3 square pyramids, corners with two equivalent IK2Sm2 tetrahedra, corners with two equivalent IK2Sm3 trigonal bipyramids, an edgeedge with one IK2Sm3 square pyramid, an edgeedge with one IK2Sm2 tetrahedra, and edges with two equivalent IK2Sm3 trigonal bipyramids. In the second I1- site, I1- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Sm2+ atoms. In the third I1- site, I1- is bonded to two equivalent K1+ and three Sm2+ atoms to form distorted IK2Sm3 trigonal bipyramids that share corners with four equivalent IK2Sm3 square pyramids, corners with two equivalent IK2Sm2 tetrahedra, corners with four equivalent IK2Sm3 trigonal bipyramids, an edgeedge with one IK2Sm3 square pyramid, edges with two equivalent IK2Sm2 tetrahedra, and a faceface with one IK2Sm3 square pyramid. In the fourth I1- site, I1- is bonded to two equivalent K1+ and three Sm2+ atoms to form distorted IK2Sm3 square pyramids that share corners with four equivalent IK2Sm2 tetrahedra, corners with four equivalent IK2Sm3 trigonal bipyramids, edges with two equivalent IK2Sm3 square pyramids, an edgeedge with one IK2Sm2 tetrahedra, an edgeedge with one IK2Sm3 trigonal bipyramid, and a faceface with one IK2Sm3 trigonal bipyramid. In the fifth I1- site, I1- is bonded in a 4-coordinate geometry to four Sm2+ atoms.