CaSmCuO3Cl crystallizes in the tetragonal P4/nmm space group. Ca(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent Cl(1) atoms. Sm(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(1) and one Cl(1) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), two equivalent Sm(1), and two equivalent Cu(1) atoms to form distorted OCa2Sm2Cu2 octahedra that share corners with two equivalent O(1)Ca2Sm2Cu2 octahedra, corners with six equivalent O(2)Sm4 tetrahedra, edges with two equivalent O(1)Ca2Sm2Cu2 octahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and faces with four equivalent O(1)Ca2Sm2Cu2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second O site, O(2) is bonded to four equivalent Sm(1) atoms to form OSm4 tetrahedra that share corners with twelve equivalent O(1)Ca2Sm2Cu2 octahedra, corners with four equivalent O(2)Sm4 tetrahedra, edges with two equivalent O(1)Ca2Sm2Cu2 octahedra, and edges with four equivalent O(2)Sm4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-69°. Cl(1) is bonded in a distorted hexagonal planar geometry to five equivalent Ca(1) and one Cu(1) atom.
CaSmCuO3Cl crystallizes in the tetragonal P4/nmm space group. Ca(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent Cl(1) atoms. All Ca(1)-O(1) bond lengths are 2.49 Å. There are four shorter (3.01 Å) and one longer (3.19 Å) Ca(1)-Cl(1) bond length. Sm(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All Sm(1)-O(1) bond lengths are 2.70 Å. All Sm(1)-O(2) bond lengths are 2.30 Å. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(1) and one Cl(1) atom. All Cu(1)-O(1) bond lengths are 1.96 Å. The Cu(1)-Cl(1) bond length is 2.76 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), two equivalent Sm(1), and two equivalent Cu(1) atoms to form distorted OCa2Sm2Cu2 octahedra that share corners with two equivalent O(1)Ca2Sm2Cu2 octahedra, corners with six equivalent O(2)Sm4 tetrahedra, edges with two equivalent O(1)Ca2Sm2Cu2 octahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and faces with four equivalent O(1)Ca2Sm2Cu2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second O site, O(2) is bonded to four equivalent Sm(1) atoms to form OSm4 tetrahedra that share corners with twelve equivalent O(1)Ca2Sm2Cu2 octahedra, corners with four equivalent O(2)Sm4 tetrahedra, edges with two equivalent O(1)Ca2Sm2Cu2 octahedra, and edges with four equivalent O(2)Sm4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-69°. Cl(1) is bonded in a distorted hexagonal planar geometry to five equivalent Ca(1) and one Cu(1) atom.