Mg2Te3O8 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms. In the second Te site, Te(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one Te(2) atom. In the second O site, O(1) is bonded to two equivalent Mg(1) and two equivalent Te(2) atoms to form distorted edge-sharing OMg2Te2 tetrahedra. In the third O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Te(1), and one Te(2) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mg(1), one Te(1), and one Te(2) atom.
Mg2Te3O8 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 56°. The Mg(1)-O(2) bond length is 2.13 Å. The Mg(1)-O(3) bond length is 2.03 Å. There is one shorter (2.16 Å) and one longer (2.26 Å) Mg(1)-O(1) bond length. There is one shorter (2.03 Å) and one longer (2.06 Å) Mg(1)-O(4) bond length. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms. Both Te(1)-O(2) bond lengths are 2.10 Å. Both Te(1)-O(3) bond lengths are 1.87 Å. In the second Te site, Te(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. The Te(2)-O(2) bond length is 1.96 Å. The Te(2)-O(3) bond length is 2.70 Å. The Te(2)-O(4) bond length is 1.88 Å. There is one shorter (1.93 Å) and one longer (2.32 Å) Te(2)-O(1) bond length. There are four inequivalent O sites. In the first O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one Te(2) atom. In the second O site, O(1) is bonded to two equivalent Mg(1) and two equivalent Te(2) atoms to form distorted edge-sharing OMg2Te2 tetrahedra. In the third O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Te(1), and one Te(2) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mg(1), one Te(1), and one Te(2) atom.