MgCo2Zn2(SiO5)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(8), and one O(9) atom to form distorted MgO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Co(2)O4 trigonal pyramids,  an edgeedge with one Si(1)O4 tetrahedra,  an edgeedge with one Si(2)O4 tetrahedra, and  an edgeedge with one Co(1)O5 trigonal bipyramid. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(2), one O(4), one O(7), and one O(9) atom to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Co(2)O4 trigonal pyramids, and  an edgeedge with one Mg(1)O6 octahedra. In the second Co site, Co(2) is bonded to one O(1), one O(10), one O(6), and one O(9) atom to form distorted CoO4 trigonal pyramids that share corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Co(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 52-75°. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted see-saw-like geometry to one O(10), one O(3), one O(4), and one O(8) atom. In the second Zn site, Zn(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(5), one O(6), and one O(9) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Co(1)O5 trigonal bipyramids,  a cornercorner with one Co(2)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O6 octahedra. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid,  a cornercorner with one Co(2)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(2), one Zn(2), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one Zn(2), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Zn(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(1), one Zn(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Zn(2), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Co(2), one Zn(2), and one Si(2) atom. In the seventh O site, O(7) is bonded in a linear geometry to one Co(1) and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Zn(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted tetrahedral geometry to one Mg(1), one Co(1), one Co(2), and one Zn(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one Co(2), and one Zn(1) atom.
MgCo2Zn2(SiO5)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(8), and one O(9) atom to form distorted MgO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Co(2)O4 trigonal pyramids,  an edgeedge with one Si(1)O4 tetrahedra,  an edgeedge with one Si(2)O4 tetrahedra, and  an edgeedge with one Co(1)O5 trigonal bipyramid. The Mg(1)-O(1) bond length is 2.26 Å. The Mg(1)-O(3) bond length is 2.13 Å. The Mg(1)-O(4) bond length is 2.34 Å. The Mg(1)-O(5) bond length is 1.98 Å. The Mg(1)-O(8) bond length is 2.07 Å. The Mg(1)-O(9) bond length is 2.03 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(2), one O(4), one O(7), and one O(9) atom to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Co(2)O4 trigonal pyramids, and  an edgeedge with one Mg(1)O6 octahedra. The Co(1)-O(10) bond length is 1.90 Å. The Co(1)-O(2) bond length is 2.07 Å. The Co(1)-O(4) bond length is 2.17 Å. The Co(1)-O(7) bond length is 1.77 Å. The Co(1)-O(9) bond length is 2.00 Å. In the second Co site, Co(2) is bonded to one O(1), one O(10), one O(6), and one O(9) atom to form distorted CoO4 trigonal pyramids that share corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Co(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 52-75°. The Co(2)-O(1) bond length is 1.97 Å. The Co(2)-O(10) bond length is 1.79 Å. The Co(2)-O(6) bond length is 1.90 Å. The Co(2)-O(9) bond length is 1.87 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted see-saw-like geometry to one O(10), one O(3), one O(4), and one O(8) atom. The Zn(1)-O(10) bond length is 1.96 Å. The Zn(1)-O(3) bond length is 2.07 Å. The Zn(1)-O(4) bond length is 2.16 Å. The Zn(1)-O(8) bond length is 1.95 Å. In the second Zn site, Zn(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(5), one O(6), and one O(9) atom. The Zn(2)-O(1) bond length is 2.24 Å. The Zn(2)-O(2) bond length is 2.04 Å. The Zn(2)-O(5) bond length is 2.13 Å. The Zn(2)-O(6) bond length is 2.02 Å. The Zn(2)-O(9) bond length is 2.04 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Co(1)O5 trigonal bipyramids,  a cornercorner with one Co(2)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O6 octahedra. The Si(1)-O(1) bond length is 1.66 Å. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(7) bond length is 1.65 Å. The Si(1)-O(8) bond length is 1.64 Å. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid,  a cornercorner with one Co(2)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. The Si(2)-O(3) bond length is 1.65 Å. The Si(2)-O(4) bond length is 1.67 Å. The Si(2)-O(5) bond length is 1.62 Å. The Si(2)-O(6) bond length is 1.69 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(2), one Zn(2), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one Zn(2), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Zn(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(1), one Zn(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Zn(2), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Co(2), one Zn(2), and one Si(2) atom. In the seventh O site, O(7) is bonded in a linear geometry to one Co(1) and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Zn(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted tetrahedral geometry to one Mg(1), one Co(1), one Co(2), and one Zn(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one Co(2), and one Zn(1) atom.