Er3S2OF3 crystallizes in the monoclinic Cc space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms. In the second Er site, Er(2) is bonded in a 2-coordinate geometry to two equivalent S(2), three equivalent S(1), one O(1), one F(2), and one F(3) atom. In the third Er site, Er(3) is bonded in a 2-coordinate geometry to two equivalent S(1), three equivalent S(2), one O(1), one F(1), and one F(3) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Er(3) and three equivalent Er(2) atoms to form a mixture of distorted corner and edge-sharing SEr5 trigonal bipyramids. In the second S site, S(2) is bonded to two equivalent Er(2) and three equivalent Er(3) atoms to form a mixture of distorted corner and edge-sharing SEr5 trigonal bipyramids. O(1) is bonded in a 4-coordinate geometry to one Er(2), one Er(3), and two equivalent Er(1) atoms. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal planar geometry to one Er(3) and two equivalent Er(1) atoms. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Er(2) and two equivalent Er(1) atoms. In the third F site, F(3) is bonded in a 4-coordinate geometry to one Er(2), one Er(3), and two equivalent Er(1) atoms.
Er3S2OF3 crystallizes in the monoclinic Cc space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent F(1), two equivalent F(2), and two equivalent F(3) atoms. Both Er(1)-O(1) bond lengths are 2.28 Å. There is one shorter (2.28 Å) and one longer (2.33 Å) Er(1)-F(1) bond length. Both Er(1)-F(2) bond lengths are 2.32 Å. There is one shorter (2.28 Å) and one longer (2.34 Å) Er(1)-F(3) bond length. In the second Er site, Er(2) is bonded in a 2-coordinate geometry to two equivalent S(2), three equivalent S(1), one O(1), one F(2), and one F(3) atom. There is one shorter (2.75 Å) and one longer (2.88 Å) Er(2)-S(2) bond length. There are a spread of Er(2)-S(1) bond distances ranging from 2.76-2.91 Å. The Er(2)-O(1) bond length is 2.15 Å. The Er(2)-F(2) bond length is 2.28 Å. The Er(2)-F(3) bond length is 2.86 Å. In the third Er site, Er(3) is bonded in a 2-coordinate geometry to two equivalent S(1), three equivalent S(2), one O(1), one F(1), and one F(3) atom. There is one shorter (2.72 Å) and one longer (2.86 Å) Er(3)-S(1) bond length. There are a spread of Er(3)-S(2) bond distances ranging from 2.74-2.84 Å. The Er(3)-O(1) bond length is 2.79 Å. The Er(3)-F(1) bond length is 2.28 Å. The Er(3)-F(3) bond length is 2.28 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Er(3) and three equivalent Er(2) atoms to form a mixture of distorted corner and edge-sharing SEr5 trigonal bipyramids. In the second S site, S(2) is bonded to two equivalent Er(2) and three equivalent Er(3) atoms to form a mixture of distorted corner and edge-sharing SEr5 trigonal bipyramids. O(1) is bonded in a 4-coordinate geometry to one Er(2), one Er(3), and two equivalent Er(1) atoms. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal planar geometry to one Er(3) and two equivalent Er(1) atoms. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Er(2) and two equivalent Er(1) atoms. In the third F site, F(3) is bonded in a 4-coordinate geometry to one Er(2), one Er(3), and two equivalent Er(1) atoms.