Er2WO6 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(1), one O(2), one O(4), one O(5), one O(6), and two equivalent O(3) atoms. In the second Er site, Er(2) is bonded to one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form distorted ErO7 hexagonal pyramids that share corners with three equivalent W(1)O6 octahedra, edges with two equivalent Er(2)O7 hexagonal pyramids, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-46°. W(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 WO6 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(6) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one W(1) atom. In the second O site, O(1) is bonded to one Er(1), two equivalent Er(2), and one W(1) atom to form a mixture of corner and edge-sharing OEr3W tetrahedra. In the third O site, O(2) is bonded to one Er(1), two equivalent Er(2), and one W(1) atom to form a mixture of distorted corner and edge-sharing OEr3W tetrahedra. In the fourth O site, O(3) is bonded in a trigonal planar geometry to two equivalent Er(1) and one W(1) atom. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Er(2), and one W(1) atom. In the sixth O site, O(5) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one W(1) atom.
Er2WO6 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(1), one O(2), one O(4), one O(5), one O(6), and two equivalent O(3) atoms. The Er(1)-O(1) bond length is 2.26 Å. The Er(1)-O(2) bond length is 2.55 Å. The Er(1)-O(4) bond length is 2.28 Å. The Er(1)-O(5) bond length is 2.27 Å. The Er(1)-O(6) bond length is 2.36 Å. There is one shorter (2.20 Å) and one longer (2.21 Å) Er(1)-O(3) bond length. In the second Er site, Er(2) is bonded to one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms to form distorted ErO7 hexagonal pyramids that share corners with three equivalent W(1)O6 octahedra, edges with two equivalent Er(2)O7 hexagonal pyramids, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-46°. The Er(2)-O(4) bond length is 2.29 Å. The Er(2)-O(5) bond length is 2.25 Å. The Er(2)-O(6) bond length is 2.31 Å. There is one shorter (2.29 Å) and one longer (2.37 Å) Er(2)-O(1) bond length. There is one shorter (2.25 Å) and one longer (2.36 Å) Er(2)-O(2) bond length. W(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 WO6 octahedra that share corners with three equivalent Er(2)O7 hexagonal pyramids and edges with two equivalent Er(2)O7 hexagonal pyramids. The W(1)-O(1) bond length is 2.00 Å. The W(1)-O(2) bond length is 1.96 Å. The W(1)-O(3) bond length is 1.94 Å. The W(1)-O(4) bond length is 1.89 Å. The W(1)-O(5) bond length is 1.86 Å. The W(1)-O(6) bond length is 1.91 Å. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one W(1) atom. In the second O site, O(1) is bonded to one Er(1), two equivalent Er(2), and one W(1) atom to form a mixture of corner and edge-sharing OEr3W tetrahedra. In the third O site, O(2) is bonded to one Er(1), two equivalent Er(2), and one W(1) atom to form a mixture of distorted corner and edge-sharing OEr3W tetrahedra. In the fourth O site, O(3) is bonded in a trigonal planar geometry to two equivalent Er(1) and one W(1) atom. In the fifth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Er(1), one Er(2), and one W(1) atom. In the sixth O site, O(5) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one W(1) atom.