Mg2TaSbO6 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(4), and two equivalent O(1) atoms. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Ta(1)O6 octahedra and corners with four equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 62-81°. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra, and corners with four equivalent Mg(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-52°. Sb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Ta(1)O6 octahedra, and corners with four equivalent Mg(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-55°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Ta(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(2), one Ta(1), and one Sb(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Mg(2), and two equivalent Sb(1) atoms to form distorted OMg2Sb2 tetrahedra that share corners with two equivalent O(3)Mg2Sb2 tetrahedra and corners with two equivalent O(4)Mg2Ta2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), and two equivalent Ta(1) atoms to form distorted OMg2Ta2 trigonal pyramids that share corners with two equivalent O(3)Mg2Sb2 tetrahedra and corners with two equivalent O(4)Mg2Ta2 trigonal pyramids.
Mg2TaSbO6 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(4), and two equivalent O(1) atoms. The Mg(1)-O(3) bond length is 2.04 Å. The Mg(1)-O(4) bond length is 2.26 Å. Both Mg(1)-O(1) bond lengths are 2.05 Å. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Ta(1)O6 octahedra and corners with four equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 62-81°. The Mg(2)-O(3) bond length is 2.06 Å. The Mg(2)-O(4) bond length is 2.09 Å. Both Mg(2)-O(2) bond lengths are 2.04 Å. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra, and corners with four equivalent Mg(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-52°. Both Ta(1)-O(1) bond lengths are 1.97 Å. Both Ta(1)-O(2) bond lengths are 1.99 Å. Both Ta(1)-O(4) bond lengths are 2.14 Å. Sb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Ta(1)O6 octahedra, and corners with four equivalent Mg(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-55°. Both Sb(1)-O(1) bond lengths are 2.27 Å. Both Sb(1)-O(2) bond lengths are 2.37 Å. Both Sb(1)-O(3) bond lengths are 2.22 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Ta(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(2), one Ta(1), and one Sb(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Mg(2), and two equivalent Sb(1) atoms to form distorted OMg2Sb2 tetrahedra that share corners with two equivalent O(3)Mg2Sb2 tetrahedra and corners with two equivalent O(4)Mg2Ta2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), and two equivalent Ta(1) atoms to form distorted OMg2Ta2 trigonal pyramids that share corners with two equivalent O(3)Mg2Sb2 tetrahedra and corners with two equivalent O(4)Mg2Ta2 trigonal pyramids.