Materials Data on Ca3Mg by Materials Project

Abstract

MgCa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to eight equivalent Ca and four equivalent Mg atoms to form CaCa8Mg4 cuboctahedra that share corners with four equivalent CaCa8Mg4 cuboctahedra, corners with eight equivalent MgCa12 cuboctahedra, edges with twenty-four CaCa8Mg4 cuboctahedra, faces with six equivalent MgCa12 cuboctahedra, and faces with twelve CaCa8Mg4 cuboctahedra. All Ca–Ca bond lengths are 3.73 Å. All Ca–Mg bond lengths are 3.72 Å. In the second Ca site, Ca is bonded to eight Ca and four equivalent Mg atoms to form CaCa8Mg4 cuboctahedra that share corners with twelve equivalent CaCa8Mg4 cuboctahedra, edges with eight equivalent MgCa12 cuboctahedra, edges with sixteen CaCa8Mg4 cuboctahedra, faces with four equivalent MgCa12 cuboctahedra, and faces with fourteen CaCa8Mg4 cuboctahedra. All Ca–Ca bond lengths are 3.72 Å. All Ca–Mg bond lengths are 3.73 Å. Mg is bonded to twelve Ca atoms to form MgCa12 cuboctahedra that share corners with four equivalent MgCa12 cuboctahedra, corners with eight equivalent CaCa8Mg4 cuboctahedra, edges with eight equivalent MgCa12 cuboctahedra, edges with sixteen equivalent CaCa8Mg4 cuboctahedra, faces with four equivalent MgCa12 cuboctahedra, and faces with fourteen CaCa8Mg4 cuboctahedra.