MgBi5 crystallizes in the hexagonal P-62m space group. Mg(1) is bonded to six equivalent Bi(1) and six equivalent Bi(2) atoms to form MgBi12 cuboctahedra that share corners with eighteen equivalent Bi(1)Mg3Bi9 cuboctahedra, edges with six equivalent Mg(1)Bi12 cuboctahedra, faces with two equivalent Mg(1)Bi12 cuboctahedra, and faces with six equivalent Bi(1)Mg3Bi9 cuboctahedra. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to three equivalent Mg(1), three equivalent Bi(1), and six equivalent Bi(2) atoms to form distorted BiMg3Bi9 cuboctahedra that share corners with nine equivalent Mg(1)Bi12 cuboctahedra, corners with nine equivalent Bi(1)Mg3Bi9 cuboctahedra, edges with six equivalent Bi(1)Mg3Bi9 cuboctahedra, faces with three equivalent Mg(1)Bi12 cuboctahedra, and faces with five equivalent Bi(1)Mg3Bi9 cuboctahedra. In the second Bi site, Bi(2) is bonded in a 2-coordinate geometry to two equivalent Mg(1) and four equivalent Bi(1) atoms.
MgBi5 crystallizes in the hexagonal P-62m space group. Mg(1) is bonded to six equivalent Bi(1) and six equivalent Bi(2) atoms to form MgBi12 cuboctahedra that share corners with eighteen equivalent Bi(1)Mg3Bi9 cuboctahedra, edges with six equivalent Mg(1)Bi12 cuboctahedra, faces with two equivalent Mg(1)Bi12 cuboctahedra, and faces with six equivalent Bi(1)Mg3Bi9 cuboctahedra. All Mg(1)-Bi(1) bond lengths are 3.51 Å. All Mg(1)-Bi(2) bond lengths are 3.41 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to three equivalent Mg(1), three equivalent Bi(1), and six equivalent Bi(2) atoms to form distorted BiMg3Bi9 cuboctahedra that share corners with nine equivalent Mg(1)Bi12 cuboctahedra, corners with nine equivalent Bi(1)Mg3Bi9 cuboctahedra, edges with six equivalent Bi(1)Mg3Bi9 cuboctahedra, faces with three equivalent Mg(1)Bi12 cuboctahedra, and faces with five equivalent Bi(1)Mg3Bi9 cuboctahedra. All Bi(1)-Bi(1) bond lengths are 3.51 Å. All Bi(1)-Bi(2) bond lengths are 3.54 Å. In the second Bi site, Bi(2) is bonded in a 2-coordinate geometry to two equivalent Mg(1) and four equivalent Bi(1) atoms.