Er2TeO6 crystallizes in the orthorhombic P2_12_12_1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. In the second Er site, Er(2) is bonded to one O(2), one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms to form distorted ErO7 hexagonal pyramids that share corners with three equivalent Te(1)O6 octahedra, edges with two equivalent Er(2)O7 hexagonal pyramids, and edges with two equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-46°. Te(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form TeO6 octahedra that share corners with three equivalent Er(2)O7 hexagonal pyramids and edges with two equivalent Er(2)O7 hexagonal pyramids. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Er(1) and one Te(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one Te(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Er(2), and one Te(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Er(1), one Er(2), and one Te(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Er(1), two equivalent Er(2), and one Te(1) atom. In the sixth O site, O(6) is bonded to one Er(1), two equivalent Er(2), and one Te(1) atom to form distorted corner-sharing OEr3Te tetrahedra.
Er2TeO6 crystallizes in the orthorhombic P2_12_12_1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. The Er(1)-O(2) bond length is 2.25 Å. The Er(1)-O(3) bond length is 2.27 Å. The Er(1)-O(4) bond length is 2.39 Å. The Er(1)-O(5) bond length is 2.58 Å. The Er(1)-O(6) bond length is 2.26 Å. There is one shorter (2.20 Å) and one longer (2.23 Å) Er(1)-O(1) bond length. In the second Er site, Er(2) is bonded to one O(2), one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms to form distorted ErO7 hexagonal pyramids that share corners with three equivalent Te(1)O6 octahedra, edges with two equivalent Er(2)O7 hexagonal pyramids, and edges with two equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-46°. The Er(2)-O(2) bond length is 2.22 Å. The Er(2)-O(3) bond length is 2.28 Å. The Er(2)-O(4) bond length is 2.26 Å. There is one shorter (2.28 Å) and one longer (2.43 Å) Er(2)-O(5) bond length. There is one shorter (2.33 Å) and one longer (2.46 Å) Er(2)-O(6) bond length. Te(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form TeO6 octahedra that share corners with three equivalent Er(2)O7 hexagonal pyramids and edges with two equivalent Er(2)O7 hexagonal pyramids. The Te(1)-O(1) bond length is 1.91 Å. The Te(1)-O(2) bond length is 1.89 Å. The Te(1)-O(3) bond length is 1.90 Å. The Te(1)-O(4) bond length is 1.93 Å. The Te(1)-O(5) bond length is 1.94 Å. The Te(1)-O(6) bond length is 1.95 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Er(1) and one Te(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one Te(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Er(2), and one Te(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Er(1), one Er(2), and one Te(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Er(1), two equivalent Er(2), and one Te(1) atom. In the sixth O site, O(6) is bonded to one Er(1), two equivalent Er(2), and one Te(1) atom to form distorted corner-sharing OEr3Te tetrahedra.