ErCuTe2O6Cl crystallizes in the monoclinic P2_1/c space group. Er(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(4), one O(5), and one Cl(1) atom. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(6) atom. In the second Te site, Te(2) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Er(1) and one Te(1) atom. In the second O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Er(1) and one Te(2) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Er(1), one Cu(1), and one Te(2) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Er(1), one Cu(1), and one Te(2) atom. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Cu(1), and one Te(1) atom. In the sixth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Cu(1), and one Te(1) atom. Cl(1) is bonded in a distorted single-bond geometry to one Cu(1) atom.
ErCuTe2O6Cl crystallizes in the monoclinic P2_1/c space group. Er(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. The Er(1)-O(2) bond length is 2.32 Å. The Er(1)-O(3) bond length is 2.58 Å. The Er(1)-O(4) bond length is 2.44 Å. The Er(1)-O(5) bond length is 2.31 Å. There is one shorter (2.31 Å) and one longer (2.34 Å) Er(1)-O(1) bond length. There is one shorter (2.33 Å) and one longer (2.36 Å) Er(1)-O(6) bond length. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(4), one O(5), and one Cl(1) atom. The Cu(1)-O(2) bond length is 2.01 Å. The Cu(1)-O(3) bond length is 1.94 Å. The Cu(1)-O(4) bond length is 1.93 Å. The Cu(1)-O(5) bond length is 1.99 Å. The Cu(1)-Cl(1) bond length is 2.79 Å. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(6) atom. The Te(1)-O(4) bond length is 1.93 Å. The Te(1)-O(5) bond length is 1.91 Å. The Te(1)-O(6) bond length is 1.92 Å. In the second Te site, Te(2) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(3) atom. The Te(2)-O(1) bond length is 1.89 Å. The Te(2)-O(2) bond length is 1.91 Å. The Te(2)-O(3) bond length is 1.94 Å. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Er(1) and one Te(1) atom. In the second O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Er(1) and one Te(2) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Er(1), one Cu(1), and one Te(2) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Er(1), one Cu(1), and one Te(2) atom. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Cu(1), and one Te(1) atom. In the sixth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Cu(1), and one Te(1) atom. Cl(1) is bonded in a distorted single-bond geometry to one Cu(1) atom.