Materials Data on CaMg by Materials Project

Abstract

MgCa crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to twelve Ca atoms to form a mixture of edge, face, and corner-sharing CaCa12 cuboctahedra. There are six shorter (3.69 Å) and six longer (3.89 Å) Ca–Ca bond lengths. In the second Ca site, Ca is bonded to three equivalent Ca and three equivalent Mg atoms to form distorted CaCa3Mg3 cuboctahedra that share corners with twelve CaCa12 cuboctahedra, edges with twelve CaCa12 cuboctahedra, and a faceface with one CaCa3Mg3 cuboctahedra. All Ca–Mg bond lengths are 3.47 Å. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 6-coordinate geometry to three equivalent Ca and three equivalent Mg atoms. All Mg–Mg bond lengths are 3.20 Å. In the second Mg site, Mg is bonded in a 6-coordinate geometry to six equivalent Mg atoms.