U2(PbSn)3 crystallizes in the orthorhombic Pmmm space group. U(1) is bonded to two equivalent Pb(2), four equivalent Pb(1), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Sn(3) atoms to form USn6Pb6 cuboctahedra that share corners with twelve equivalent U(1)Sn6Pb6 cuboctahedra, edges with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(2)U4Pb8 cuboctahedra, edges with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with two equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(2)U4Pb8 cuboctahedra, faces with two equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, and faces with six equivalent U(1)Sn6Pb6 cuboctahedra. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to four equivalent U(1), two equivalent Pb(2), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Sn(3) atoms to form distorted PbU4Sn6Pb2 cuboctahedra that share corners with twelve equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(2)U4Pb8 cuboctahedra, edges with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, faces with two equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(2)U4Pb8 cuboctahedra, faces with two equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, and faces with six equivalent Pb(1)U4Sn6Pb2 cuboctahedra. In the second Pb site, Pb(2) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Sn(2) atoms to form distorted PbU4Sn4Pb4 cuboctahedra that share corners with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, corners with eight equivalent Sn(1)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with eight equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, and faces with four equivalent Sn(2)U4Pb8 cuboctahedra. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Sn(3) atoms to form distorted SnU4Sn4Pb4 cuboctahedra that share corners with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, corners with eight equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with eight equivalent Sn(2)U4Pb8 cuboctahedra, faces with two equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, and faces with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra. In the second Sn site, Sn(2) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Pb(2) atoms to form SnU4Pb8 cuboctahedra that share corners with four equivalent Sn(2)U4Pb8 cuboctahedra, corners with eight equivalent Sn(3)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with eight equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, and faces with four equivalent Sn(2)U4Pb8 cuboctahedra. In the third Sn site, Sn(3) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Sn(1) atoms to form distorted SnU4Sn4Pb4 cuboctahedra that share corners with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra, corners with eight equivalent Sn(2)U4Pb8 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with two equivalent Sn(2)U4Pb8 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, and faces with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra.
U2(PbSn)3 crystallizes in the orthorhombic Pmmm space group. U(1) is bonded to two equivalent Pb(2), four equivalent Pb(1), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Sn(3) atoms to form USn6Pb6 cuboctahedra that share corners with twelve equivalent U(1)Sn6Pb6 cuboctahedra, edges with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(2)U4Pb8 cuboctahedra, edges with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with two equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(2)U4Pb8 cuboctahedra, faces with two equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, and faces with six equivalent U(1)Sn6Pb6 cuboctahedra. Both U(1)-Pb(2) bond lengths are 3.37 Å. All U(1)-Pb(1) bond lengths are 3.32 Å. Both U(1)-Sn(1) bond lengths are 3.31 Å. Both U(1)-Sn(2) bond lengths are 3.36 Å. Both U(1)-Sn(3) bond lengths are 3.30 Å. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to four equivalent U(1), two equivalent Pb(2), two equivalent Sn(1), two equivalent Sn(2), and two equivalent Sn(3) atoms to form distorted PbU4Sn6Pb2 cuboctahedra that share corners with twelve equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(2)U4Pb8 cuboctahedra, edges with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, edges with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, faces with two equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(2)U4Pb8 cuboctahedra, faces with two equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, and faces with six equivalent Pb(1)U4Sn6Pb2 cuboctahedra. Both Pb(1)-Pb(2) bond lengths are 3.35 Å. Both Pb(1)-Sn(1) bond lengths are 3.31 Å. Both Pb(1)-Sn(2) bond lengths are 3.36 Å. Both Pb(1)-Sn(3) bond lengths are 3.33 Å. In the second Pb site, Pb(2) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Sn(2) atoms to form distorted PbU4Sn4Pb4 cuboctahedra that share corners with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, corners with eight equivalent Sn(1)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with eight equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, and faces with four equivalent Sn(2)U4Pb8 cuboctahedra. All Pb(2)-Sn(2) bond lengths are 3.32 Å. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Sn(3) atoms to form distorted SnU4Sn4Pb4 cuboctahedra that share corners with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, corners with eight equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with eight equivalent Sn(2)U4Pb8 cuboctahedra, faces with two equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, and faces with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra. All Sn(1)-Sn(3) bond lengths are 3.32 Å. In the second Sn site, Sn(2) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Pb(2) atoms to form SnU4Pb8 cuboctahedra that share corners with four equivalent Sn(2)U4Pb8 cuboctahedra, corners with eight equivalent Sn(3)U4Sn4Pb4 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, edges with eight equivalent Sn(1)U4Sn4Pb4 cuboctahedra, faces with two equivalent Sn(3)U4Sn4Pb4 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(2)U4Sn4Pb4 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, and faces with four equivalent Sn(2)U4Pb8 cuboctahedra. In the third Sn site, Sn(3) is bonded to four equivalent U(1), four equivalent Pb(1), and four equivalent Sn(1) atoms to form distorted SnU4Sn4Pb4 cuboctahedra that share corners with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra, corners with eight equivalent Sn(2)U4Pb8 cuboctahedra, edges with eight equivalent U(1)Sn6Pb6 cuboctahedra, edges with eight equivalent Pb(2)U4Sn4Pb4 cuboctahedra, edges with eight equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with two equivalent Sn(2)U4Pb8 cuboctahedra, faces with four equivalent U(1)Sn6Pb6 cuboctahedra, faces with four equivalent Pb(1)U4Sn6Pb2 cuboctahedra, faces with four equivalent Sn(1)U4Sn4Pb4 cuboctahedra, and faces with four equivalent Sn(3)U4Sn4Pb4 cuboctahedra.