Sm2(CuAs)3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to three equivalent Cu(3), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. In the second Sm site, Sm(2) is bonded in a 11-coordinate geometry to one Cu(3), two equivalent Cu(1), two equivalent Cu(2), one As(2), two equivalent As(1), and three equivalent As(3) atoms. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Sm(2), one As(1), and three equivalent As(2) atoms to form distorted CuSm2As4 tetrahedra that share corners with four equivalent As(3)Sm5Cu2 pentagonal bipyramids,  an edgeedge with one As(3)Sm5Cu2 pentagonal bipyramid, and edges with four equivalent Cu(1)Sm2As4 tetrahedra. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to two equivalent Sm(2), two equivalent Cu(3), one As(1), one As(3), and two equivalent As(2) atoms. In the third Cu site, Cu(3) is bonded in a 10-coordinate geometry to one Sm(2), three equivalent Sm(1), two equivalent Cu(2), one As(2), one As(3), and two equivalent As(1) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Sm(1), two equivalent Sm(2), one Cu(1), one Cu(2), and two equivalent Cu(3) atoms. In the second As site, As(2) is bonded in a 9-coordinate geometry to one Sm(2), two equivalent Sm(1), one Cu(3), two equivalent Cu(2), and three equivalent Cu(1) atoms. In the third As site, As(3) is bonded to two equivalent Sm(1), three equivalent Sm(2), one Cu(2), and one Cu(3) atom to form distorted AsSm5Cu2 pentagonal bipyramids that share corners with four equivalent Cu(1)Sm2As4 tetrahedra, edges with four equivalent As(3)Sm5Cu2 pentagonal bipyramids, and  an edgeedge with one Cu(1)Sm2As4 tetrahedra.
Sm2(CuAs)3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to three equivalent Cu(3), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. There is one shorter (3.22 Å) and two longer (3.24 Å) Sm(1)-Cu(3) bond lengths. Both Sm(1)-As(1) bond lengths are 3.06 Å. Both Sm(1)-As(2) bond lengths are 3.11 Å. Both Sm(1)-As(3) bond lengths are 2.97 Å. In the second Sm site, Sm(2) is bonded in a 11-coordinate geometry to one Cu(3), two equivalent Cu(1), two equivalent Cu(2), one As(2), two equivalent As(1), and three equivalent As(3) atoms. The Sm(2)-Cu(3) bond length is 3.05 Å. Both Sm(2)-Cu(1) bond lengths are 3.31 Å. Both Sm(2)-Cu(2) bond lengths are 3.26 Å. The Sm(2)-As(2) bond length is 2.96 Å. Both Sm(2)-As(1) bond lengths are 2.96 Å. There are two shorter (2.90 Å) and one longer (3.02 Å) Sm(2)-As(3) bond length. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Sm(2), one As(1), and three equivalent As(2) atoms to form distorted CuSm2As4 tetrahedra that share corners with four equivalent As(3)Sm5Cu2 pentagonal bipyramids,  an edgeedge with one As(3)Sm5Cu2 pentagonal bipyramid, and edges with four equivalent Cu(1)Sm2As4 tetrahedra. The Cu(1)-As(1) bond length is 2.49 Å. There are two shorter (2.49 Å) and one longer (2.55 Å) Cu(1)-As(2) bond length. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to two equivalent Sm(2), two equivalent Cu(3), one As(1), one As(3), and two equivalent As(2) atoms. Both Cu(2)-Cu(3) bond lengths are 2.64 Å. The Cu(2)-As(1) bond length is 2.51 Å. The Cu(2)-As(3) bond length is 2.47 Å. Both Cu(2)-As(2) bond lengths are 2.62 Å. In the third Cu site, Cu(3) is bonded in a 10-coordinate geometry to one Sm(2), three equivalent Sm(1), two equivalent Cu(2), one As(2), one As(3), and two equivalent As(1) atoms. The Cu(3)-As(2) bond length is 2.44 Å. The Cu(3)-As(3) bond length is 2.55 Å. Both Cu(3)-As(1) bond lengths are 2.51 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Sm(1), two equivalent Sm(2), one Cu(1), one Cu(2), and two equivalent Cu(3) atoms. In the second As site, As(2) is bonded in a 9-coordinate geometry to one Sm(2), two equivalent Sm(1), one Cu(3), two equivalent Cu(2), and three equivalent Cu(1) atoms. In the third As site, As(3) is bonded to two equivalent Sm(1), three equivalent Sm(2), one Cu(2), and one Cu(3) atom to form distorted AsSm5Cu2 pentagonal bipyramids that share corners with four equivalent Cu(1)Sm2As4 tetrahedra, edges with four equivalent As(3)Sm5Cu2 pentagonal bipyramids, and  an edgeedge with one Cu(1)Sm2As4 tetrahedra.