Ca2TaMnO6 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), two equivalent O(4), and four equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), two equivalent O(3), and four equivalent O(4) atoms. Ta(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra and corners with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-32°. Mn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-32°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to one Ca(1), one Ca(2), and two equivalent Mn(1) atoms to form distorted corner-sharing OCa2Mn2 tetrahedra. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(2), two equivalent Ca(1), one Ta(1), and one Mn(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Ca(1), two equivalent Ca(2), one Ta(1), and one Mn(1) atom.
Ca2TaMnO6 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), two equivalent O(4), and four equivalent O(3) atoms. The Ca(1)-O(1) bond length is 2.56 Å. The Ca(1)-O(2) bond length is 2.35 Å. Both Ca(1)-O(4) bond lengths are 2.56 Å. There are two shorter (2.39 Å) and two longer (2.78 Å) Ca(1)-O(3) bond lengths. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), two equivalent O(3), and four equivalent O(4) atoms. The Ca(2)-O(1) bond length is 2.35 Å. The Ca(2)-O(2) bond length is 2.36 Å. Both Ca(2)-O(3) bond lengths are 2.66 Å. There are two shorter (2.38 Å) and two longer (2.68 Å) Ca(2)-O(4) bond lengths. Ta(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra and corners with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-32°. Both Ta(1)-O(1) bond lengths are 2.00 Å. Both Ta(1)-O(3) bond lengths are 2.01 Å. Both Ta(1)-O(4) bond lengths are 1.97 Å. Mn(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-32°. Both Mn(1)-O(2) bond lengths are 2.01 Å. Both Mn(1)-O(3) bond lengths are 1.99 Å. Both Mn(1)-O(4) bond lengths are 2.27 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to one Ca(1), one Ca(2), and two equivalent Mn(1) atoms to form distorted corner-sharing OCa2Mn2 tetrahedra. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(2), two equivalent Ca(1), one Ta(1), and one Mn(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Ca(1), two equivalent Ca(2), one Ta(1), and one Mn(1) atom.