Materials Data on Ca5Mg by Materials Project

Abstract

Ca5Mg crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are three inequivalent Ca sites. In the first Ca site, Ca is bonded to three equivalent Ca and three equivalent Mg atoms to form a mixture of distorted edge, face, and corner-sharing CaCa3Mg3 cuboctahedra. All Ca–Ca bond lengths are 3.99 Å. All Ca–Mg bond lengths are 3.53 Å. In the second Ca site, Ca is bonded to twelve Ca atoms to form CaCa12 cuboctahedra that share corners with eighteen CaCa3Mg3 cuboctahedra, edges with eighteen CaCa3Mg3 cuboctahedra, and faces with thirteen CaCa12 cuboctahedra. There are six shorter (3.82 Å) and three longer (3.96 Å) Ca–Ca bond lengths. In the third Ca site, Ca is bonded to twelve Ca atoms to form CaCa12 cuboctahedra that share corners with eighteen CaCa3Mg3 cuboctahedra, edges with eighteen CaCa12 cuboctahedra, and faces with twenty CaCa3Mg3 cuboctahedra. All Ca–Ca bond lengths are 3.82 Å. Mg is bonded in a 6-coordinate geometry to six equivalent Ca atoms.