MgYCu(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted MgO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with four equivalent W(1)O6 octahedra, edges with two equivalent Y(1)O6 octahedra, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-57°. Y(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form YO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-59°. 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(7), and one O(8) atom to form WO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Y(1)O6 octahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. In the second W site, W(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted WO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Y(1)O6 octahedra, edges with two equivalent W(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-59°. Cu(1) is bonded in a distorted trigonal planar geometry to one O(2), one O(6), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Y(1), and one W(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Y(1), one W(1), and one Cu(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one W(1), and one W(2) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Y(1), one W(1), and one W(2) atom to form a mixture of distorted corner and edge-sharing OYMgW2 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Y(1), and one W(2) atom. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(1), one Y(1), one W(2), and one Cu(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Y(1), one W(1), and one W(2) atom. In the eighth O site, O(8) is bonded to one Mg(1), one W(1), one W(2), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMgCuW2 tetrahedra.
MgYCu(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted MgO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with four equivalent W(1)O6 octahedra, edges with two equivalent Y(1)O6 octahedra, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-57°. The Mg(1)-O(1) bond length is 2.09 Å. The Mg(1)-O(3) bond length is 2.07 Å. The Mg(1)-O(4) bond length is 2.36 Å. The Mg(1)-O(5) bond length is 2.06 Å. The Mg(1)-O(6) bond length is 2.22 Å. The Mg(1)-O(8) bond length is 2.27 Å. Y(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(7) atom to form YO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-59°. The Y(1)-O(1) bond length is 2.23 Å. The Y(1)-O(2) bond length is 2.24 Å. The Y(1)-O(4) bond length is 2.33 Å. The Y(1)-O(5) bond length is 2.38 Å. The Y(1)-O(6) bond length is 2.26 Å. The Y(1)-O(7) bond length is 2.27 Å. 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(7), and one O(8) atom to form WO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Y(1)O6 octahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. The W(1)-O(1) bond length is 2.00 Å. The W(1)-O(2) bond length is 1.88 Å. The W(1)-O(3) bond length is 2.05 Å. The W(1)-O(4) bond length is 2.20 Å. The W(1)-O(7) bond length is 2.04 Å. The W(1)-O(8) bond length is 2.11 Å. In the second W site, W(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted WO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Y(1)O6 octahedra, edges with two equivalent W(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-59°. The W(2)-O(3) bond length is 2.08 Å. The W(2)-O(4) bond length is 2.05 Å. The W(2)-O(5) bond length is 1.88 Å. The W(2)-O(6) bond length is 2.00 Å. The W(2)-O(7) bond length is 2.07 Å. The W(2)-O(8) bond length is 2.12 Å. Cu(1) is bonded in a distorted trigonal planar geometry to one O(2), one O(6), and one O(8) atom. The Cu(1)-O(2) bond length is 2.08 Å. The Cu(1)-O(6) bond length is 1.91 Å. The Cu(1)-O(8) bond length is 1.95 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Y(1), and one W(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Y(1), one W(1), and one Cu(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one W(1), and one W(2) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Y(1), one W(1), and one W(2) atom to form a mixture of distorted corner and edge-sharing OYMgW2 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Y(1), and one W(2) atom. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(1), one Y(1), one W(2), and one Cu(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Y(1), one W(1), and one W(2) atom. In the eighth O site, O(8) is bonded to one Mg(1), one W(1), one W(2), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMgCuW2 tetrahedra.