Mg5Pb crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(5), and four equivalent Mg(4) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg2Pb2 cuboctahedra, corners with four equivalent Mg(5)Mg2Pb2 cuboctahedra, corners with four equivalent Mg(2)Mg2Pb4 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with eight equivalent Pb(1)Mg10 cuboctahedra, faces with two equivalent Pb(1)Mg10 cuboctahedra, and faces with four equivalent Mg(1)Mg12 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1) and four equivalent Pb(1) atoms to form distorted MgMg2Pb4 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg2Pb4 cuboctahedra, corners with six equivalent Mg(3)Mg2Pb2 cuboctahedra, corners with eight equivalent Mg(5)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(5)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(2)Mg2Pb4 cuboctahedra, edges with three equivalent Mg(3)Mg2Pb2 cuboctahedra, edges with four equivalent Mg(4)Mg4Pb2 cuboctahedra, faces with two equivalent Mg(2)Mg2Pb4 cuboctahedra, and faces with two equivalent Mg(4)Mg4Pb2 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1) and two equivalent Pb(1) atoms to form distorted MgMg2Pb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(3)Mg2Pb2 cuboctahedra, corners with six equivalent Mg(2)Mg2Pb4 cuboctahedra, corners with eight equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with two equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with three equivalent Mg(2)Mg2Pb4 cuboctahedra, and edges with four equivalent Mg(5)Mg2Pb2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to four equivalent Mg(1) and two equivalent Pb(1) atoms to form distorted MgMg4Pb2 cuboctahedra that share corners with four equivalent Mg(4)Mg4Pb2 cuboctahedra, corners with six equivalent Mg(5)Mg2Pb2 cuboctahedra, corners with eight equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(3)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with three equivalent Mg(5)Mg2Pb2 cuboctahedra, edges with four equivalent Mg(2)Mg2Pb4 cuboctahedra, faces with two equivalent Mg(2)Mg2Pb4 cuboctahedra, and faces with two equivalent Mg(4)Mg4Pb2 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to two equivalent Mg(1) and two equivalent Pb(1) atoms to form distorted MgMg2Pb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(5)Mg2Pb2 cuboctahedra, corners with six equivalent Mg(4)Mg4Pb2 cuboctahedra, corners with eight equivalent Mg(2)Mg2Pb4 cuboctahedra, edges with two equivalent Mg(2)Mg2Pb4 cuboctahedra, edges with three equivalent Mg(4)Mg4Pb2 cuboctahedra, and edges with four equivalent Mg(3)Mg2Pb2 cuboctahedra. Pb(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(2) atoms to form distorted PbMg10 cuboctahedra that share corners with four equivalent Pb(1)Mg10 cuboctahedra, edges with eight equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, and faces with four equivalent Pb(1)Mg10 cuboctahedra.
Mg5Pb crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(5), and four equivalent Mg(4) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Mg2Pb2 cuboctahedra, corners with four equivalent Mg(5)Mg2Pb2 cuboctahedra, corners with four equivalent Mg(2)Mg2Pb4 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with eight equivalent Pb(1)Mg10 cuboctahedra, faces with two equivalent Pb(1)Mg10 cuboctahedra, and faces with four equivalent Mg(1)Mg12 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.24 Å. Both Mg(1)-Mg(2) bond lengths are 3.19 Å. Both Mg(1)-Mg(3) bond lengths are 3.15 Å. Both Mg(1)-Mg(5) bond lengths are 3.21 Å. All Mg(1)-Mg(4) bond lengths are 3.21 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1) and four equivalent Pb(1) atoms to form distorted MgMg2Pb4 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg2Pb4 cuboctahedra, corners with six equivalent Mg(3)Mg2Pb2 cuboctahedra, corners with eight equivalent Mg(5)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(5)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(2)Mg2Pb4 cuboctahedra, edges with three equivalent Mg(3)Mg2Pb2 cuboctahedra, edges with four equivalent Mg(4)Mg4Pb2 cuboctahedra, faces with two equivalent Mg(2)Mg2Pb4 cuboctahedra, and faces with two equivalent Mg(4)Mg4Pb2 cuboctahedra. All Mg(2)-Pb(1) bond lengths are 3.23 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1) and two equivalent Pb(1) atoms to form distorted MgMg2Pb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(3)Mg2Pb2 cuboctahedra, corners with six equivalent Mg(2)Mg2Pb4 cuboctahedra, corners with eight equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with two equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with three equivalent Mg(2)Mg2Pb4 cuboctahedra, and edges with four equivalent Mg(5)Mg2Pb2 cuboctahedra. Both Mg(3)-Pb(1) bond lengths are 3.24 Å. In the fourth Mg site, Mg(4) is bonded to four equivalent Mg(1) and two equivalent Pb(1) atoms to form distorted MgMg4Pb2 cuboctahedra that share corners with four equivalent Mg(4)Mg4Pb2 cuboctahedra, corners with six equivalent Mg(5)Mg2Pb2 cuboctahedra, corners with eight equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(3)Mg2Pb2 cuboctahedra, edges with two equivalent Mg(4)Mg4Pb2 cuboctahedra, edges with three equivalent Mg(5)Mg2Pb2 cuboctahedra, edges with four equivalent Mg(2)Mg2Pb4 cuboctahedra, faces with two equivalent Mg(2)Mg2Pb4 cuboctahedra, and faces with two equivalent Mg(4)Mg4Pb2 cuboctahedra. Both Mg(4)-Pb(1) bond lengths are 3.25 Å. In the fifth Mg site, Mg(5) is bonded to two equivalent Mg(1) and two equivalent Pb(1) atoms to form distorted MgMg2Pb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(5)Mg2Pb2 cuboctahedra, corners with six equivalent Mg(4)Mg4Pb2 cuboctahedra, corners with eight equivalent Mg(2)Mg2Pb4 cuboctahedra, edges with two equivalent Mg(2)Mg2Pb4 cuboctahedra, edges with three equivalent Mg(4)Mg4Pb2 cuboctahedra, and edges with four equivalent Mg(3)Mg2Pb2 cuboctahedra. Both Mg(5)-Pb(1) bond lengths are 3.19 Å. Pb(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), and four equivalent Mg(2) atoms to form distorted PbMg10 cuboctahedra that share corners with four equivalent Pb(1)Mg10 cuboctahedra, edges with eight equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, and faces with four equivalent Pb(1)Mg10 cuboctahedra.