Er5B2(O2F3)3 crystallizes in the monoclinic C2/c space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), two equivalent O(2), one F(2), two equivalent F(1), and two equivalent F(4) atoms. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one F(1), one F(3), one F(5), and two equivalent F(2) atoms. In the third Er site, Er(3) is bonded in a 9-coordinate geometry to two equivalent O(1), two equivalent O(3), one F(3), and four equivalent F(5) atoms. B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are three inequivalent O sites. In the first O site, O(2) is bonded in a distorted single-bond geometry to one Er(2), two equivalent Er(1), and one B(1) atom. In the second O site, O(3) is bonded in a distorted single-bond geometry to one Er(1), one Er(2), one Er(3), and one B(1) atom. In the third O site, O(1) is bonded in a distorted single-bond geometry to one Er(1), one Er(2), one Er(3), and one B(1) atom. There are five inequivalent F sites. In the first F site, F(5) is bonded in a distorted trigonal planar geometry to one Er(2) and two equivalent Er(3) atoms. In the second F site, F(3) is bonded in a distorted trigonal non-coplanar geometry to one Er(3) and two equivalent Er(2) atoms. In the third F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to one Er(2) and two equivalent Er(1) atoms. In the fourth F site, F(2) is bonded in a distorted trigonal non-coplanar geometry to one Er(1) and two equivalent Er(2) atoms. In the fifth F site, F(4) is bonded in a distorted bent 150 degrees geometry to two equivalent Er(1) atoms.
Er5B2(O2F3)3 crystallizes in the monoclinic C2/c space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), two equivalent O(2), one F(2), two equivalent F(1), and two equivalent F(4) atoms. The Er(1)-O(1) bond length is 2.56 Å. The Er(1)-O(3) bond length is 2.50 Å. There is one shorter (2.33 Å) and one longer (2.34 Å) Er(1)-O(2) bond length. The Er(1)-F(2) bond length is 2.41 Å. There is one shorter (2.27 Å) and one longer (2.34 Å) Er(1)-F(1) bond length. There is one shorter (2.20 Å) and one longer (2.22 Å) Er(1)-F(4) bond length. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one F(1), one F(3), one F(5), and two equivalent F(2) atoms. The Er(2)-O(1) bond length is 2.31 Å. The Er(2)-O(2) bond length is 2.41 Å. The Er(2)-O(3) bond length is 2.33 Å. The Er(2)-F(1) bond length is 2.34 Å. The Er(2)-F(3) bond length is 2.50 Å. The Er(2)-F(5) bond length is 2.22 Å. There is one shorter (2.26 Å) and one longer (2.28 Å) Er(2)-F(2) bond length. In the third Er site, Er(3) is bonded in a 9-coordinate geometry to two equivalent O(1), two equivalent O(3), one F(3), and four equivalent F(5) atoms. Both Er(3)-O(1) bond lengths are 2.33 Å. Both Er(3)-O(3) bond lengths are 2.36 Å. The Er(3)-F(3) bond length is 2.27 Å. There are two shorter (2.41 Å) and two longer (2.66 Å) Er(3)-F(5) bond lengths. B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The B(1)-O(1) bond length is 1.38 Å. The B(1)-O(2) bond length is 1.40 Å. The B(1)-O(3) bond length is 1.39 Å. There are three inequivalent O sites. In the first O site, O(2) is bonded in a distorted single-bond geometry to one Er(2), two equivalent Er(1), and one B(1) atom. In the second O site, O(3) is bonded in a distorted single-bond geometry to one Er(1), one Er(2), one Er(3), and one B(1) atom. In the third O site, O(1) is bonded in a distorted single-bond geometry to one Er(1), one Er(2), one Er(3), and one B(1) atom. There are five inequivalent F sites. In the first F site, F(5) is bonded in a distorted trigonal planar geometry to one Er(2) and two equivalent Er(3) atoms. In the second F site, F(3) is bonded in a distorted trigonal non-coplanar geometry to one Er(3) and two equivalent Er(2) atoms. In the third F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to one Er(2) and two equivalent Er(1) atoms. In the fourth F site, F(2) is bonded in a distorted trigonal non-coplanar geometry to one Er(1) and two equivalent Er(2) atoms. In the fifth F site, F(4) is bonded in a distorted bent 150 degrees geometry to two equivalent Er(1) atoms.