Materials Data on Ca(BeGe)2 by Materials Project

Abstract

CaBe2Ge2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to eight Be and eight Ge atoms. There are four shorter (3.08 Å) and four longer (3.16 Å) Ca–Be bond lengths. There are four shorter (3.06 Å) and four longer (3.22 Å) Ca–Ge bond lengths. There are two inequivalent Be sites. In the first Be site, Be is bonded in a 9-coordinate geometry to four equivalent Ca and five Ge atoms. There are one shorter (2.30 Å) and four longer (2.42 Å) Be–Ge bond lengths. In the second Be site, Be is bonded to four equivalent Ca and four equivalent Ge atoms to form distorted BeCa4Ge4 tetrahedra that share corners with twelve equivalent GeCa4Be4 tetrahedra, edges with two equivalent GeCa4Be4 tetrahedra, edges with four equivalent BeCa4Ge4 tetrahedra, and faces with four equivalent BeCa4Ge4 tetrahedra. All Be–Ge bond lengths are 2.40 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded to four equivalent Ca and four equivalent Be atoms to form distorted GeCa4Be4 tetrahedra that share corners with twelve equivalent BeCa4Ge4 tetrahedra, edges with two equivalent BeCa4Ge4 tetrahedra, edges with four equivalent GeCa4Be4 tetrahedra, and faces with four equivalent GeCa4Be4 tetrahedra. In the second Ge site, Ge is bonded in a 9-coordinate geometry to four equivalent Ca and five Be atoms.