Materials Data on Ca2Mg by Materials Project

Abstract

Ca2Mg crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to six Ca and six equivalent Mg atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with twelve CaCa8Mg4 cuboctahedra, edges with eleven equivalent CaCa8Mg4 cuboctahedra, and faces with fourteen CaCa6Mg6 cuboctahedra. There are two shorter (3.61 Å) and four longer (3.75 Å) Ca–Ca bond lengths. There are two shorter (3.59 Å) and four longer (3.68 Å) Ca–Mg bond lengths. In the second Ca site, Ca is bonded to eight Ca and four equivalent Mg atoms to form a mixture of distorted corner, edge, and face-sharing CaCa8Mg4 cuboctahedra. There are four shorter (3.62 Å) and two longer (3.75 Å) Ca–Ca bond lengths. There are two shorter (3.52 Å) and two longer (3.71 Å) Ca–Mg bond lengths. Mg is bonded in a 10-coordinate geometry to ten Ca atoms.