Materials Data on Ca5Mg by Materials Project

Abstract

Ca5Mg crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Ca sites. In the first Ca site, Ca is bonded to ten Ca and two equivalent Mg atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with twelve CaCa10Mg2 cuboctahedra, edges with nine CaCa8Mg2 cuboctahedra, and faces with fourteen CaCa10Mg2 cuboctahedra. There are a spread of Ca–Ca bond distances ranging from 3.75–4.00 Å. Both Ca–Mg bond lengths are 3.65 Å. In the second Ca site, Ca is bonded in a 11-coordinate geometry to nine Ca and two equivalent Mg atoms. There are a spread of Ca–Ca bond distances ranging from 3.59–3.83 Å. Both Ca–Mg bond lengths are 3.75 Å. In the third Ca site, Ca is bonded to eight Ca and two equivalent Mg atoms to form distorted CaCa8Mg2 cuboctahedra that share corners with fourteen CaCa8Mg2 cuboctahedra, edges with five CaCa10Mg2 cuboctahedra, and faces with fourteen CaCa10Mg2 cuboctahedra. There are a spread of Ca–Ca bond distances ranging from 3.83–3.99 Å. Both Ca–Mg bond lengths are 3.64 Å. In the fourth Ca site, Ca is bonded to eleven Ca and one Mg atom to form a mixture of distorted corner, edge, and face-sharing CaCa11Mg cuboctahedra. There are two shorter (3.82 Å) and two longer (3.84 Å) Ca–Ca bond lengths. The Ca–Mg bond length is 3.71 Å. In the fifth Ca site, Ca is bonded to ten Ca and two equivalent Mg atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with fourteen CaCa8Mg2 cuboctahedra, edges with nine CaCa10Mg2 cuboctahedra, and faces with thirteen CaCa10Mg2 cuboctahedra. Both Ca–Ca bond lengths are 3.82 Å. Both Ca–Mg bond lengths are 3.69 Å. Mg is bonded in a 9-coordinate geometry to nine Ca atoms.