BeSmCu4 crystallizes in the hexagonal P-6m2 space group. Be(1) is bonded in a 6-coordinate geometry to three equivalent Sm(1), three equivalent Cu(1), and six equivalent Cu(2) atoms. Sm(1) is bonded in a 18-coordinate geometry to three equivalent Be(1), three equivalent Cu(1), and twelve equivalent Cu(2) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Be(1), three equivalent Sm(1), and six equivalent Cu(2) atoms to form distorted CuSm3Be3Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Sm4Be2Cu6 cuboctahedra, edges with six equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, faces with two equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Sm4Be2Cu6 cuboctahedra. In the second Cu site, Cu(2) is bonded to two equivalent Be(1), four equivalent Sm(1), two equivalent Cu(1), and four equivalent Cu(2) atoms to form distorted CuSm4Be2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, corners with sixteen equivalent Cu(2)Sm4Be2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Sm4Be2Cu6 cuboctahedra, faces with six equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Sm4Be2Cu6 cuboctahedra.
BeSmCu4 crystallizes in the hexagonal P-6m2 space group. Be(1) is bonded in a 6-coordinate geometry to three equivalent Sm(1), three equivalent Cu(1), and six equivalent Cu(2) atoms. All Be(1)-Sm(1) bond lengths are 2.96 Å. All Be(1)-Cu(1) bond lengths are 2.96 Å. All Be(1)-Cu(2) bond lengths are 2.41 Å. Sm(1) is bonded in a 18-coordinate geometry to three equivalent Be(1), three equivalent Cu(1), and twelve equivalent Cu(2) atoms. All Sm(1)-Cu(1) bond lengths are 2.96 Å. All Sm(1)-Cu(2) bond lengths are 3.21 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Be(1), three equivalent Sm(1), and six equivalent Cu(2) atoms to form distorted CuSm3Be3Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Sm4Be2Cu6 cuboctahedra, edges with six equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, faces with two equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Sm4Be2Cu6 cuboctahedra. All Cu(1)-Cu(2) bond lengths are 2.46 Å. In the second Cu site, Cu(2) is bonded to two equivalent Be(1), four equivalent Sm(1), two equivalent Cu(1), and four equivalent Cu(2) atoms to form distorted CuSm4Be2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, corners with sixteen equivalent Cu(2)Sm4Be2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Sm4Be2Cu6 cuboctahedra, faces with six equivalent Cu(1)Sm3Be3Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Sm4Be2Cu6 cuboctahedra. There are two shorter (2.48 Å) and two longer (2.64 Å) Cu(2)-Cu(2) bond lengths.