Sm4OCl6 crystallizes in the hexagonal P6_3mc space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 1-coordinate geometry to one O(1), two equivalent Cl(1), and three equivalent Cl(2) atoms. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(1), three equivalent Cl(1), and three equivalent Cl(2) atoms. O(1) is bonded to one Sm(2) and three equivalent Sm(1) atoms to form OSm4 trigonal pyramids that share corners with six equivalent Cl(2)Sm4 tetrahedra and edges with three equivalent Cl(2)Sm4 tetrahedra. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 3-coordinate geometry to one Sm(2) and two equivalent Sm(1) atoms. In the second Cl site, Cl(2) is bonded to one Sm(2) and three equivalent Sm(1) atoms to form distorted ClSm4 tetrahedra that share corners with eight equivalent Cl(2)Sm4 tetrahedra, corners with two equivalent O(1)Sm4 trigonal pyramids, and  an edgeedge with one O(1)Sm4 trigonal pyramid.
Sm4OCl6 crystallizes in the hexagonal P6_3mc space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 1-coordinate geometry to one O(1), two equivalent Cl(1), and three equivalent Cl(2) atoms. The Sm(1)-O(1) bond length is 2.25 Å. Both Sm(1)-Cl(1) bond lengths are 2.90 Å. There are two shorter (2.82 Å) and one longer (2.93 Å) Sm(1)-Cl(2) bond length. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(1), three equivalent Cl(1), and three equivalent Cl(2) atoms. The Sm(2)-O(1) bond length is 2.34 Å. All Sm(2)-Cl(1) bond lengths are 2.99 Å. All Sm(2)-Cl(2) bond lengths are 2.98 Å. O(1) is bonded to one Sm(2) and three equivalent Sm(1) atoms to form OSm4 trigonal pyramids that share corners with six equivalent Cl(2)Sm4 tetrahedra and edges with three equivalent Cl(2)Sm4 tetrahedra. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 3-coordinate geometry to one Sm(2) and two equivalent Sm(1) atoms. In the second Cl site, Cl(2) is bonded to one Sm(2) and three equivalent Sm(1) atoms to form distorted ClSm4 tetrahedra that share corners with eight equivalent Cl(2)Sm4 tetrahedra, corners with two equivalent O(1)Sm4 trigonal pyramids, and  an edgeedge with one O(1)Sm4 trigonal pyramid.