SmCu4Al crystallizes in the hexagonal P-6m2 space group. Sm(1) is bonded in a 18-coordinate geometry to three equivalent Cu(1), twelve equivalent Cu(2), and three equivalent Al(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Sm(1), six equivalent Cu(2), and three equivalent Al(1) atoms to form CuSm3Al3Cu6 cuboctahedra that share corners with nine equivalent Al(1)Sm3Cu9 cuboctahedra, corners with twelve equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, edges with six equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, faces with two equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, faces with three equivalent Al(1)Sm3Cu9 cuboctahedra, and faces with eighteen equivalent Cu(2)Sm4Al2Cu6 cuboctahedra. In the second Cu site, Cu(2) is bonded to four equivalent Sm(1), two equivalent Cu(1), four equivalent Cu(2), and two equivalent Al(1) atoms to form distorted CuSm4Al2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, corners with four equivalent Al(1)Sm3Cu9 cuboctahedra, corners with sixteen equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, faces with six equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, faces with six equivalent Al(1)Sm3Cu9 cuboctahedra, and faces with ten equivalent Cu(2)Sm4Al2Cu6 cuboctahedra. Al(1) is bonded to three equivalent Sm(1), three equivalent Cu(1), and six equivalent Cu(2) atoms to form distorted AlSm3Cu9 cuboctahedra that share corners with nine equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, corners with twelve equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, edges with six equivalent Al(1)Sm3Cu9 cuboctahedra, faces with two equivalent Al(1)Sm3Cu9 cuboctahedra, faces with three equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Sm4Al2Cu6 cuboctahedra.
SmCu4Al crystallizes in the hexagonal P-6m2 space group. Sm(1) is bonded in a 18-coordinate geometry to three equivalent Cu(1), twelve equivalent Cu(2), and three equivalent Al(1) atoms. All Sm(1)-Cu(1) bond lengths are 3.04 Å. All Sm(1)-Cu(2) bond lengths are 3.31 Å. All Sm(1)-Al(1) bond lengths are 3.04 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Sm(1), six equivalent Cu(2), and three equivalent Al(1) atoms to form CuSm3Al3Cu6 cuboctahedra that share corners with nine equivalent Al(1)Sm3Cu9 cuboctahedra, corners with twelve equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, edges with six equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, faces with two equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, faces with three equivalent Al(1)Sm3Cu9 cuboctahedra, and faces with eighteen equivalent Cu(2)Sm4Al2Cu6 cuboctahedra. All Cu(1)-Cu(2) bond lengths are 2.50 Å. All Cu(1)-Al(1) bond lengths are 3.04 Å. In the second Cu site, Cu(2) is bonded to four equivalent Sm(1), two equivalent Cu(1), four equivalent Cu(2), and two equivalent Al(1) atoms to form distorted CuSm4Al2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, corners with four equivalent Al(1)Sm3Cu9 cuboctahedra, corners with sixteen equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, faces with six equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, faces with six equivalent Al(1)Sm3Cu9 cuboctahedra, and faces with ten equivalent Cu(2)Sm4Al2Cu6 cuboctahedra. There are two shorter (2.62 Å) and two longer (2.66 Å) Cu(2)-Cu(2) bond lengths. Both Cu(2)-Al(1) bond lengths are 2.52 Å. Al(1) is bonded to three equivalent Sm(1), three equivalent Cu(1), and six equivalent Cu(2) atoms to form distorted AlSm3Cu9 cuboctahedra that share corners with nine equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, corners with twelve equivalent Cu(2)Sm4Al2Cu6 cuboctahedra, edges with six equivalent Al(1)Sm3Cu9 cuboctahedra, faces with two equivalent Al(1)Sm3Cu9 cuboctahedra, faces with three equivalent Cu(1)Sm3Al3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Sm4Al2Cu6 cuboctahedra.