Tb2SeOF2 crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Tb sites. In the first Tb site, Tb(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 Tb site, Tb(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 Tb(2) and four equivalent Tb(1) atoms to form distorted SeTb6 pentagonal pyramids that share corners with four equivalent Se(1)Tb6 pentagonal pyramids, corners with four equivalent F(2)Tb4 tetrahedra, corners with six equivalent O(1)Tb4 tetrahedra, edges with two equivalent Se(1)Tb6 pentagonal pyramids, edges with three equivalent F(2)Tb4 tetrahedra, edges with four equivalent O(1)Tb4 tetrahedra, and faces with two equivalent Se(1)Tb6 pentagonal pyramids. O(1) is bonded to one Tb(2) and three equivalent Tb(1) atoms to form OTb4 tetrahedra that share corners with six equivalent Se(1)Tb6 pentagonal pyramids, corners with two equivalent O(1)Tb4 tetrahedra, corners with two equivalent F(2)Tb4 tetrahedra, edges with four equivalent Se(1)Tb6 pentagonal pyramids, edges with two equivalent O(1)Tb4 tetrahedra, and edges with two equivalent F(2)Tb4 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 Tb(2) atoms. In the second F site, F(2) is bonded to one Tb(1) and three equivalent Tb(2) atoms to form FTb4 tetrahedra that share corners with four equivalent Se(1)Tb6 pentagonal pyramids, corners with two equivalent O(1)Tb4 tetrahedra, corners with six equivalent F(2)Tb4 tetrahedra, edges with three equivalent Se(1)Tb6 pentagonal pyramids, and edges with two equivalent O(1)Tb4 tetrahedra.
Tb2SeOF2 crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Tb sites. In the first Tb site, Tb(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 (3.02 Å) and two longer (3.04 Å) Tb(1)-Se(1) bond lengths. There is one shorter (2.26 Å) and two longer (2.27 Å) Tb(1)-O(1) bond lengths. The Tb(1)-F(2) bond length is 2.41 Å. In the second Tb site, Tb(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 Tb(2)-Se(1) bond lengths are 3.04 Å. The Tb(2)-O(1) bond length is 2.26 Å. There is one shorter (2.35 Å) and two longer (2.39 Å) Tb(2)-F(1) bond lengths. There are two shorter (2.36 Å) and one longer (2.42 Å) Tb(2)-F(2) bond length. Se(1) is bonded to two equivalent Tb(2) and four equivalent Tb(1) atoms to form distorted SeTb6 pentagonal pyramids that share corners with four equivalent Se(1)Tb6 pentagonal pyramids, corners with four equivalent F(2)Tb4 tetrahedra, corners with six equivalent O(1)Tb4 tetrahedra, edges with two equivalent Se(1)Tb6 pentagonal pyramids, edges with three equivalent F(2)Tb4 tetrahedra, edges with four equivalent O(1)Tb4 tetrahedra, and faces with two equivalent Se(1)Tb6 pentagonal pyramids. O(1) is bonded to one Tb(2) and three equivalent Tb(1) atoms to form OTb4 tetrahedra that share corners with six equivalent Se(1)Tb6 pentagonal pyramids, corners with two equivalent O(1)Tb4 tetrahedra, corners with two equivalent F(2)Tb4 tetrahedra, edges with four equivalent Se(1)Tb6 pentagonal pyramids, edges with two equivalent O(1)Tb4 tetrahedra, and edges with two equivalent F(2)Tb4 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 Tb(2) atoms. In the second F site, F(2) is bonded to one Tb(1) and three equivalent Tb(2) atoms to form FTb4 tetrahedra that share corners with four equivalent Se(1)Tb6 pentagonal pyramids, corners with two equivalent O(1)Tb4 tetrahedra, corners with six equivalent F(2)Tb4 tetrahedra, edges with three equivalent Se(1)Tb6 pentagonal pyramids, and edges with two equivalent O(1)Tb4 tetrahedra.