Mg2TaFeO6 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 8-coordinate geometry to one O(3), one O(4), two equivalent O(2), and four equivalent O(1) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one O(3), one O(4), two equivalent O(1), and four equivalent O(2) atoms. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-43°. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-44°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(2), two equivalent Mg(1), one Ta(1), and one Fe(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), two equivalent Mg(2), one Ta(1), and one Fe(1) atom. In the third O site, O(3) 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(4)Mg2Fe2 trigonal pyramids and corners with two equivalent O(3)Mg2Ta2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), and two equivalent Fe(1) atoms to form distorted OMg2Fe2 trigonal pyramids that share corners with two equivalent O(4)Mg2Fe2 trigonal pyramids and corners with two equivalent O(3)Mg2Ta2 trigonal pyramids.
Mg2TaFeO6 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 8-coordinate geometry to one O(3), one O(4), two equivalent O(2), and four equivalent O(1) atoms. The Mg(1)-O(3) bond length is 2.29 Å. The Mg(1)-O(4) bond length is 2.04 Å. Both Mg(1)-O(2) bond lengths are 2.58 Å. There are two shorter (2.07 Å) and two longer (2.73 Å) Mg(1)-O(1) bond lengths. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one O(3), one O(4), two equivalent O(1), and four equivalent O(2) atoms. The Mg(2)-O(3) bond length is 2.10 Å. The Mg(2)-O(4) bond length is 2.09 Å. Both Mg(2)-O(1) bond lengths are 2.51 Å. There are two shorter (2.12 Å) and two longer (2.71 Å) Mg(2)-O(2) bond lengths. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra and corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-43°. Both Ta(1)-O(1) bond lengths are 1.98 Å. Both Ta(1)-O(2) bond lengths are 1.98 Å. Both Ta(1)-O(3) bond lengths are 2.05 Å. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-44°. Both Fe(1)-O(1) bond lengths are 2.03 Å. Both Fe(1)-O(2) bond lengths are 2.07 Å. Both Fe(1)-O(4) bond lengths are 2.06 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(2), two equivalent Mg(1), one Ta(1), and one Fe(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), two equivalent Mg(2), one Ta(1), and one Fe(1) atom. In the third O site, O(3) 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(4)Mg2Fe2 trigonal pyramids and corners with two equivalent O(3)Mg2Ta2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), and two equivalent Fe(1) atoms to form distorted OMg2Fe2 trigonal pyramids that share corners with two equivalent O(4)Mg2Fe2 trigonal pyramids and corners with two equivalent O(3)Mg2Ta2 trigonal pyramids.