MgYCu(WO4)2 crystallizes in the triclinic P1 space group. Mg(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 MgO6 octahedra that share corners with two equivalent Y(1)O6 octahedra, edges with two equivalent W(1)O6 octahedra, edges with two equivalent W(2)O6 octahedra, and  a faceface with one Y(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-61°. 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 two equivalent Mg(1)O6 octahedra, corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-61°. 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 Y(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-54°. 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 WO6 octahedra that share corners with four equivalent Y(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-55°. Cu(1) is bonded in a distorted linear geometry to one O(2), one O(3), 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 4-coordinate geometry to one Mg(1), one Y(1), one W(1), and one Cu(1) atom. In the third O site, O(3) is bonded to one Mg(1), one W(1), one W(2), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing OMgCuW2 trigonal pyramids. 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 edge and corner-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 T-shaped geometry to one Mg(1), one Y(1), and one W(2) 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 in a distorted trigonal non-coplanar geometry to one W(1), one W(2), and one Cu(1) atom.
MgYCu(WO4)2 crystallizes in the triclinic P1 space group. Mg(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 MgO6 octahedra that share corners with two equivalent Y(1)O6 octahedra, edges with two equivalent W(1)O6 octahedra, edges with two equivalent W(2)O6 octahedra, and  a faceface with one Y(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-61°. The Mg(1)-O(1) bond length is 2.02 Å. The Mg(1)-O(2) bond length is 2.19 Å. The Mg(1)-O(3) bond length is 2.11 Å. The Mg(1)-O(4) bond length is 2.18 Å. The Mg(1)-O(5) bond length is 2.03 Å. The Mg(1)-O(6) bond length is 2.30 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 two equivalent Mg(1)O6 octahedra, corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-61°. The Y(1)-O(1) bond length is 2.24 Å. The Y(1)-O(2) bond length is 2.43 Å. The Y(1)-O(4) bond length is 2.44 Å. The Y(1)-O(5) bond length is 2.21 Å. The Y(1)-O(6) bond length is 2.36 Å. The Y(1)-O(7) bond length is 2.29 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 Y(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-54°. The W(1)-O(1) bond length is 1.99 Å. The W(1)-O(2) bond length is 1.87 Å. The W(1)-O(3) bond length is 2.18 Å. The W(1)-O(4) bond length is 2.14 Å. The W(1)-O(7) bond length is 2.04 Å. The W(1)-O(8) bond length is 2.03 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 WO6 octahedra that share corners with four equivalent Y(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-55°. The W(2)-O(3) bond length is 2.07 Å. The W(2)-O(4) bond length is 2.09 Å. The W(2)-O(5) bond length is 2.00 Å. The W(2)-O(6) bond length is 1.85 Å. The W(2)-O(7) bond length is 2.10 Å. The W(2)-O(8) bond length is 2.07 Å. Cu(1) is bonded in a distorted linear geometry to one O(2), one O(3), and one O(8) atom. The Cu(1)-O(2) bond length is 2.66 Å. The Cu(1)-O(3) bond length is 1.87 Å. The Cu(1)-O(8) bond length is 1.83 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 4-coordinate geometry to one Mg(1), one Y(1), one W(1), and one Cu(1) atom. In the third O site, O(3) is bonded to one Mg(1), one W(1), one W(2), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing OMgCuW2 trigonal pyramids. 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 edge and corner-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 T-shaped geometry to one Mg(1), one Y(1), and one W(2) 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 in a distorted trigonal non-coplanar geometry to one W(1), one W(2), and one Cu(1) atom.