MgZn2(NiS2)4 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent Ni(1), two equivalent Ni(2), two equivalent S(1), and two equivalent S(2) atoms to form distorted MgNi4S4 hexagonal bipyramids that share corners with four equivalent Zn(2)S4 tetrahedra, edges with two equivalent Ni(1)MgS5 square pyramids, edges with two equivalent S(1)MgZnNi2 tetrahedra, and edges with two equivalent S(2)MgZnNi2 tetrahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Mg(1), one S(1), one S(2), one S(3), and two equivalent S(4) atoms to form distorted NiMgS5 square pyramids that share  a cornercorner with one Ni(1)MgS5 square pyramid, corners with two equivalent Zn(2)S4 tetrahedra, corners with two equivalent S(1)MgZnNi2 tetrahedra, corners with two equivalent S(2)MgZnNi2 tetrahedra,  an edgeedge with one Mg(1)Ni4S4 hexagonal bipyramid, and  an edgeedge with one Ni(1)MgS5 square pyramid. In the second Ni site, Ni(2) is bonded in a 6-coordinate geometry to one Mg(1), one S(1), one S(2), one S(4), and two equivalent S(3) atoms. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a 4-coordinate geometry to two equivalent S(3) and two equivalent S(4) atoms. In the second Zn site, Zn(2) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form ZnS4 tetrahedra that share corners with four equivalent Mg(1)Ni4S4 hexagonal bipyramids and corners with four equivalent Ni(1)MgS5 square pyramids. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one Ni(1), one Ni(2), and one Zn(2) atom to form distorted SMgZnNi2 tetrahedra that share corners with two equivalent Ni(1)MgS5 square pyramids, corners with two equivalent S(1)MgZnNi2 tetrahedra, corners with three equivalent S(2)MgZnNi2 tetrahedra,  an edgeedge with one Mg(1)Ni4S4 hexagonal bipyramid, and  a faceface with one S(2)MgZnNi2 tetrahedra. In the second S site, S(2) is bonded to one Mg(1), one Ni(1), one Ni(2), and one Zn(2) atom to form distorted SMgZnNi2 tetrahedra that share corners with two equivalent Ni(1)MgS5 square pyramids, corners with two equivalent S(2)MgZnNi2 tetrahedra, corners with three equivalent S(1)MgZnNi2 tetrahedra,  an edgeedge with one Mg(1)Ni4S4 hexagonal bipyramid, and  a faceface with one S(1)MgZnNi2 tetrahedra. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to one Ni(1), two equivalent Ni(2), and one Zn(1) atom. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to one Ni(2), two equivalent Ni(1), and one Zn(1) atom.
MgZn2(NiS2)4 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent Ni(1), two equivalent Ni(2), two equivalent S(1), and two equivalent S(2) atoms to form distorted MgNi4S4 hexagonal bipyramids that share corners with four equivalent Zn(2)S4 tetrahedra, edges with two equivalent Ni(1)MgS5 square pyramids, edges with two equivalent S(1)MgZnNi2 tetrahedra, and edges with two equivalent S(2)MgZnNi2 tetrahedra. Both Mg(1)-Ni(1) bond lengths are 2.81 Å. Both Mg(1)-Ni(2) bond lengths are 2.71 Å. Both Mg(1)-S(1) bond lengths are 2.38 Å. Both Mg(1)-S(2) bond lengths are 2.41 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Mg(1), one S(1), one S(2), one S(3), and two equivalent S(4) atoms to form distorted NiMgS5 square pyramids that share  a cornercorner with one Ni(1)MgS5 square pyramid, corners with two equivalent Zn(2)S4 tetrahedra, corners with two equivalent S(1)MgZnNi2 tetrahedra, corners with two equivalent S(2)MgZnNi2 tetrahedra,  an edgeedge with one Mg(1)Ni4S4 hexagonal bipyramid, and  an edgeedge with one Ni(1)MgS5 square pyramid. The Ni(1)-S(1) bond length is 2.25 Å. The Ni(1)-S(2) bond length is 2.25 Å. The Ni(1)-S(3) bond length is 2.21 Å. There is one shorter (2.21 Å) and one longer (2.44 Å) Ni(1)-S(4) bond length. In the second Ni site, Ni(2) is bonded in a 6-coordinate geometry to one Mg(1), one S(1), one S(2), one S(4), and two equivalent S(3) atoms. The Ni(2)-S(1) bond length is 2.26 Å. The Ni(2)-S(2) bond length is 2.26 Å. The Ni(2)-S(4) bond length is 2.22 Å. There is one shorter (2.21 Å) and one longer (2.43 Å) Ni(2)-S(3) bond length. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a 4-coordinate geometry to two equivalent S(3) and two equivalent S(4) atoms. Both Zn(1)-S(3) bond lengths are 2.66 Å. Both Zn(1)-S(4) bond lengths are 2.62 Å. In the second Zn site, Zn(2) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form ZnS4 tetrahedra that share corners with four equivalent Mg(1)Ni4S4 hexagonal bipyramids and corners with four equivalent Ni(1)MgS5 square pyramids. Both Zn(2)-S(1) bond lengths are 2.30 Å. Both Zn(2)-S(2) bond lengths are 2.29 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one Ni(1), one Ni(2), and one Zn(2) atom to form distorted SMgZnNi2 tetrahedra that share corners with two equivalent Ni(1)MgS5 square pyramids, corners with two equivalent S(1)MgZnNi2 tetrahedra, corners with three equivalent S(2)MgZnNi2 tetrahedra,  an edgeedge with one Mg(1)Ni4S4 hexagonal bipyramid, and  a faceface with one S(2)MgZnNi2 tetrahedra. In the second S site, S(2) is bonded to one Mg(1), one Ni(1), one Ni(2), and one Zn(2) atom to form distorted SMgZnNi2 tetrahedra that share corners with two equivalent Ni(1)MgS5 square pyramids, corners with two equivalent S(2)MgZnNi2 tetrahedra, corners with three equivalent S(1)MgZnNi2 tetrahedra,  an edgeedge with one Mg(1)Ni4S4 hexagonal bipyramid, and  a faceface with one S(1)MgZnNi2 tetrahedra. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to one Ni(1), two equivalent Ni(2), and one Zn(1) atom. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to one Ni(2), two equivalent Ni(1), and one Zn(1) atom.