Y2W2O9 crystallizes in the triclinic P-1 space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), one O(9), and two equivalent O(3) atoms. In the second Y site, Y(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(9), two equivalent O(7), and two equivalent O(8) atoms. There are two inequivalent W sites. In the first W site, 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 distorted corner-sharing WO6 octahedra. In the second W site, W(2) is bonded to one O(2), one O(5), one O(7), one O(8), and one O(9) atom to form corner-sharing WO5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 45-55°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Y(1), one Y(2), and one W(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(2), one W(1), and one W(2) atom. In the third O site, O(3) is bonded to one Y(2), two equivalent Y(1), and one W(1) atom to form a mixture of corner and edge-sharing OY3W trigonal pyramids. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Y(1), one Y(2), and one W(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Y(1), one W(1), and one W(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Y(1) and one W(1) atom. In the seventh O site, O(7) is bonded to one Y(1), two equivalent Y(2), and one W(2) atom to form a mixture of distorted corner and edge-sharing OY3W tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Y(2) and one W(2) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Y(1), one Y(2), and one W(2) atom.
Y2W2O9 crystallizes in the triclinic P-1 space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), one O(9), and two equivalent O(3) atoms. The Y(1)-O(1) bond length is 2.30 Å. The Y(1)-O(2) bond length is 2.51 Å. The Y(1)-O(4) bond length is 2.52 Å. The Y(1)-O(5) bond length is 2.39 Å. The Y(1)-O(6) bond length is 2.32 Å. The Y(1)-O(7) bond length is 2.48 Å. The Y(1)-O(9) bond length is 2.67 Å. There is one shorter (2.37 Å) and one longer (2.43 Å) Y(1)-O(3) bond length. In the second Y site, Y(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(9), two equivalent O(7), and two equivalent O(8) atoms. The Y(2)-O(1) bond length is 2.47 Å. The Y(2)-O(2) bond length is 2.55 Å. The Y(2)-O(3) bond length is 2.40 Å. The Y(2)-O(4) bond length is 2.37 Å. The Y(2)-O(9) bond length is 2.50 Å. There is one shorter (2.53 Å) and one longer (2.56 Å) Y(2)-O(7) bond length. There is one shorter (2.48 Å) and one longer (2.56 Å) Y(2)-O(8) bond length. There are two inequivalent W sites. In the first W site, 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 distorted corner-sharing WO6 octahedra. The W(1)-O(1) bond length is 1.84 Å. The W(1)-O(2) bond length is 2.20 Å. The W(1)-O(3) bond length is 2.01 Å. The W(1)-O(4) bond length is 1.84 Å. The W(1)-O(5) bond length is 2.10 Å. The W(1)-O(6) bond length is 1.83 Å. In the second W site, W(2) is bonded to one O(2), one O(5), one O(7), one O(8), and one O(9) atom to form corner-sharing WO5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 45-55°. The W(2)-O(2) bond length is 1.93 Å. The W(2)-O(5) bond length is 1.94 Å. The W(2)-O(7) bond length is 1.94 Å. The W(2)-O(8) bond length is 1.85 Å. The W(2)-O(9) bond length is 1.84 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Y(1), one Y(2), and one W(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(2), one W(1), and one W(2) atom. In the third O site, O(3) is bonded to one Y(2), two equivalent Y(1), and one W(1) atom to form a mixture of corner and edge-sharing OY3W trigonal pyramids. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Y(1), one Y(2), and one W(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Y(1), one W(1), and one W(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Y(1) and one W(1) atom. In the seventh O site, O(7) is bonded to one Y(1), two equivalent Y(2), and one W(2) atom to form a mixture of distorted corner and edge-sharing OY3W tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Y(2) and one W(2) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Y(1), one Y(2), and one W(2) atom.