Sm2SeOF2 crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 4-coordinate geometry to four equivalent Se(1), three equivalent O(1), and one F(2) atom. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to two equivalent Se(1), one O(1), three equivalent F(1), and three equivalent F(2) atoms. Se(1) is bonded to two equivalent Sm(2) and four equivalent Sm(1) atoms to form distorted SeSm6 pentagonal pyramids that share corners with four equivalent Se(1)Sm6 pentagonal pyramids, corners with four equivalent F(2)Sm4 tetrahedra, corners with six equivalent O(1)Sm4 tetrahedra, edges with two equivalent Se(1)Sm6 pentagonal pyramids, edges with three equivalent F(2)Sm4 tetrahedra, edges with four equivalent O(1)Sm4 tetrahedra, and faces with two equivalent Se(1)Sm6 pentagonal pyramids. O(1) is bonded to one Sm(2) and three equivalent Sm(1) atoms to form OSm4 tetrahedra that share corners with six equivalent Se(1)Sm6 pentagonal pyramids, corners with two equivalent O(1)Sm4 tetrahedra, corners with two equivalent F(2)Sm4 tetrahedra, edges with four equivalent Se(1)Sm6 pentagonal pyramids, edges with two equivalent O(1)Sm4 tetrahedra, and edges with two equivalent F(2)Sm4 tetrahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded in a trigonal non-coplanar geometry to three equivalent Sm(2) atoms. In the second F site, F(2) is bonded to one Sm(1) and three equivalent Sm(2) atoms to form FSm4 tetrahedra that share corners with four equivalent Se(1)Sm6 pentagonal pyramids, corners with two equivalent O(1)Sm4 tetrahedra, corners with six equivalent F(2)Sm4 tetrahedra, edges with three equivalent Se(1)Sm6 pentagonal pyramids, and edges with two equivalent O(1)Sm4 tetrahedra.
Sm2SeOF2 crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 4-coordinate geometry to four equivalent Se(1), three equivalent O(1), and one F(2) atom. There are two shorter (3.10 Å) and two longer (3.12 Å) Sm(1)-Se(1) bond lengths. There is one shorter (2.33 Å) and two longer (2.34 Å) Sm(1)-O(1) bond lengths. The Sm(1)-F(2) bond length is 2.48 Å. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to two equivalent Se(1), one O(1), three equivalent F(1), and three equivalent F(2) atoms. Both Sm(2)-Se(1) bond lengths are 3.13 Å. The Sm(2)-O(1) bond length is 2.33 Å. There is one shorter (2.42 Å) and two longer (2.45 Å) Sm(2)-F(1) bond lengths. There are two shorter (2.43 Å) and one longer (2.48 Å) Sm(2)-F(2) bond length. Se(1) is bonded to two equivalent Sm(2) and four equivalent Sm(1) atoms to form distorted SeSm6 pentagonal pyramids that share corners with four equivalent Se(1)Sm6 pentagonal pyramids, corners with four equivalent F(2)Sm4 tetrahedra, corners with six equivalent O(1)Sm4 tetrahedra, edges with two equivalent Se(1)Sm6 pentagonal pyramids, edges with three equivalent F(2)Sm4 tetrahedra, edges with four equivalent O(1)Sm4 tetrahedra, and faces with two equivalent Se(1)Sm6 pentagonal pyramids. O(1) is bonded to one Sm(2) and three equivalent Sm(1) atoms to form OSm4 tetrahedra that share corners with six equivalent Se(1)Sm6 pentagonal pyramids, corners with two equivalent O(1)Sm4 tetrahedra, corners with two equivalent F(2)Sm4 tetrahedra, edges with four equivalent Se(1)Sm6 pentagonal pyramids, edges with two equivalent O(1)Sm4 tetrahedra, and edges with two equivalent F(2)Sm4 tetrahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded in a trigonal non-coplanar geometry to three equivalent Sm(2) atoms. In the second F site, F(2) is bonded to one Sm(1) and three equivalent Sm(2) atoms to form FSm4 tetrahedra that share corners with four equivalent Se(1)Sm6 pentagonal pyramids, corners with two equivalent O(1)Sm4 tetrahedra, corners with six equivalent F(2)Sm4 tetrahedra, edges with three equivalent Se(1)Sm6 pentagonal pyramids, and edges with two equivalent O(1)Sm4 tetrahedra.