MgY3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Mg(1) is bonded to twelve equivalent Y(1) atoms to form MgY12 cuboctahedra that share corners with six equivalent Mg(1)Y12 cuboctahedra, corners with twelve equivalent Y(1)Y8Mg4 cuboctahedra, edges with eighteen equivalent Y(1)Y8Mg4 cuboctahedra, faces with eight equivalent Mg(1)Y12 cuboctahedra, and faces with twelve equivalent Y(1)Y8Mg4 cuboctahedra. Y(1) is bonded to four equivalent Mg(1) and eight equivalent Y(1) atoms to form YY8Mg4 cuboctahedra that share corners with four equivalent Mg(1)Y12 cuboctahedra, corners with fourteen equivalent Y(1)Y8Mg4 cuboctahedra, edges with six equivalent Mg(1)Y12 cuboctahedra, edges with twelve equivalent Y(1)Y8Mg4 cuboctahedra, faces with four equivalent Mg(1)Y12 cuboctahedra, and faces with sixteen equivalent Y(1)Y8Mg4 cuboctahedra.
MgY3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Mg(1) is bonded to twelve equivalent Y(1) atoms to form MgY12 cuboctahedra that share corners with six equivalent Mg(1)Y12 cuboctahedra, corners with twelve equivalent Y(1)Y8Mg4 cuboctahedra, edges with eighteen equivalent Y(1)Y8Mg4 cuboctahedra, faces with eight equivalent Mg(1)Y12 cuboctahedra, and faces with twelve equivalent Y(1)Y8Mg4 cuboctahedra. There are six shorter (3.46 Å) and six longer (3.53 Å) Mg(1)-Y(1) bond lengths. Y(1) is bonded to four equivalent Mg(1) and eight equivalent Y(1) atoms to form YY8Mg4 cuboctahedra that share corners with four equivalent Mg(1)Y12 cuboctahedra, corners with fourteen equivalent Y(1)Y8Mg4 cuboctahedra, edges with six equivalent Mg(1)Y12 cuboctahedra, edges with twelve equivalent Y(1)Y8Mg4 cuboctahedra, faces with four equivalent Mg(1)Y12 cuboctahedra, and faces with sixteen equivalent Y(1)Y8Mg4 cuboctahedra. There are a spread of Y(1)-Y(1) bond distances ranging from 3.45-3.61 Å.