MgNi(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), 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 Ni(1)O6 octahedra, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-58°. There are two inequivalent W sites. In the first W site, W(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 WO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Ni(1)O6 octahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-58°. In the second W site, W(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted WO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Ni(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 39-58°. Ni(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form NiO6 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 37-56°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(1), one W(2), and one Ni(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Mg(1), one W(2), and one Ni(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one W(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one W(1) and one Ni(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal pyramidal geometry to one Mg(1), one W(1), one W(2), and one Ni(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one W(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(2), and one Ni(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one Ni(1) atom.
MgNi(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), 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 Ni(1)O6 octahedra, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-58°. The Mg(1)-O(2) bond length is 2.33 Å. The Mg(1)-O(3) bond length is 2.08 Å. The Mg(1)-O(5) bond length is 2.17 Å. The Mg(1)-O(6) bond length is 2.01 Å. The Mg(1)-O(7) bond length is 2.04 Å. The Mg(1)-O(8) bond length is 2.06 Å. There are two inequivalent W sites. In the first W site, W(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 WO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Ni(1)O6 octahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-58°. The W(1)-O(1) bond length is 2.02 Å. The W(1)-O(3) bond length is 1.89 Å. The W(1)-O(4) bond length is 1.78 Å. The W(1)-O(5) bond length is 2.13 Å. The W(1)-O(6) bond length is 2.25 Å. The W(1)-O(8) bond length is 1.86 Å. In the second W site, W(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted WO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Ni(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 39-58°. The W(2)-O(1) bond length is 2.05 Å. The W(2)-O(2) bond length is 1.83 Å. The W(2)-O(3) bond length is 2.19 Å. The W(2)-O(5) bond length is 2.04 Å. The W(2)-O(6) bond length is 1.90 Å. The W(2)-O(7) bond length is 1.84 Å. Ni(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form NiO6 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 37-56°. The Ni(1)-O(1) bond length is 2.14 Å. The Ni(1)-O(2) bond length is 2.06 Å. The Ni(1)-O(4) bond length is 2.03 Å. The Ni(1)-O(5) bond length is 2.27 Å. The Ni(1)-O(7) bond length is 2.14 Å. The Ni(1)-O(8) bond length is 2.07 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(1), one W(2), and one Ni(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Mg(1), one W(2), and one Ni(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one W(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one W(1) and one Ni(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal pyramidal geometry to one Mg(1), one W(1), one W(2), and one Ni(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one W(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(2), and one Ni(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one W(1), and one Ni(1) atom.