MgCo3TeO8 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Co(3)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-15°. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. In the third Co site, Co(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-15°. Te(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. There are four 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(1), one Co(3), and one Te(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(2), one Co(3), and one Te(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Co(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one Co(2), and one Te(1) atom.
MgCo3TeO8 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Co(3)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-15°. Both Mg(1)-O(1) bond lengths are 2.14 Å. Both Mg(1)-O(2) bond lengths are 2.18 Å. Both Mg(1)-O(3) bond lengths are 2.21 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. Both Co(1)-O(1) bond lengths are 2.08 Å. Both Co(1)-O(3) bond lengths are 2.09 Å. Both Co(1)-O(4) bond lengths are 2.14 Å. In the second Co site, Co(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. Both Co(2)-O(2) bond lengths are 2.17 Å. Both Co(2)-O(3) bond lengths are 1.90 Å. Both Co(2)-O(4) bond lengths are 1.94 Å. In the third Co site, Co(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-15°. Both Co(3)-O(1) bond lengths are 2.21 Å. Both Co(3)-O(2) bond lengths are 2.16 Å. Both Co(3)-O(3) bond lengths are 1.93 Å. Te(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. Both Te(1)-O(1) bond lengths are 1.96 Å. Both Te(1)-O(2) bond lengths are 1.96 Å. Both Te(1)-O(4) bond lengths are 1.96 Å. There are four 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(1), one Co(3), and one Te(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(2), one Co(3), and one Te(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Co(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one Co(2), and one Te(1) atom.