Ca8Ti3Mn5O20 crystallizes in the triclinic P1 space group. There are eight inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(10), one O(14), one O(17), one O(18), one O(2), one O(8), and one O(9) atom. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(15), one O(3), one O(6), and one O(8) atom. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one O(10), one O(16), one O(20), one O(7), one O(8), and one O(9) atom. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to one O(1), one O(19), one O(3), one O(6), one O(7), and one O(9) atom. In the fifth Ca site, Ca(5) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(17), one O(18), one O(2), and one O(4) atom. In the sixth Ca site, Ca(6) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(15), one O(18), one O(5), and one O(6) atom. In the seventh Ca site, Ca(7) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(16), one O(2), one O(20), and one O(4) atom. In the eighth Ca site, Ca(8) is bonded in a 5-coordinate geometry to one O(1), one O(12), one O(13), one O(19), and one O(3) atom. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(14), one O(4), and one O(7) atom to form TiO4 tetrahedra that share  a cornercorner with one Ti(3)O4 tetrahedra,  a cornercorner with one Ti(2)O5 trigonal bipyramid, and  a cornercorner with one Mn(1)O5 trigonal bipyramid. In the second Ti site, Ti(2) is bonded to one O(1), one O(11), one O(15), one O(16), and one O(8) atom to form TiO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Ti(1)O4 tetrahedra, and corners with two equivalent Mn(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 30-32°. In the third Ti site, Ti(3) is bonded to one O(17), one O(19), one O(4), and one O(5) atom to form TiO4 tetrahedra that share corners with two equivalent Mn(4)O5 square pyramids,  a cornercorner with one Ti(1)O4 tetrahedra, and  a cornercorner with one Mn(3)O5 trigonal bipyramid. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(12), one O(14), one O(2), one O(3), and one O(9) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O5 square pyramids, and  a cornercorner with one Ti(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 28-29°. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(15), one O(16), one O(2), and one O(3) atom to form MnO6 octahedra that share corners with two equivalent Ti(2)O5 trigonal bipyramids, corners with two equivalent Mn(1)O5 trigonal bipyramids, and corners with two equivalent Mn(5)O5 trigonal bipyramids. In the third Mn site, Mn(3) is bonded to one O(11), one O(18), one O(20), one O(5), and one O(8) atom to form distorted MnO5 trigonal bipyramids that share  a cornercorner with one Ti(3)O4 tetrahedra, corners with two equivalent Ti(2)O5 trigonal bipyramids, and corners with two equivalent Mn(5)O5 trigonal bipyramids. In the fourth Mn site, Mn(4) is bonded to one O(12), one O(17), one O(19), one O(6), and one O(9) atom to form distorted MnO5 square pyramids that share corners with two equivalent Ti(3)O4 tetrahedra,  a cornercorner with one Mn(5)O5 trigonal bipyramid, and corners with two equivalent Mn(1)O5 trigonal bipyramids. In the fifth Mn site, Mn(5) is bonded to one O(10), one O(13), one O(18), one O(20), and one O(6) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O5 square pyramid, and corners with two equivalent Mn(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 26°. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Ca(4), one Ca(8), one Ti(1), and one Ti(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(5), one Ca(7), one Mn(1), and one Mn(2) atom. In the third O site, O(3) is bonded to one Ca(2), one Ca(4), one Ca(8), one Mn(1), and one Mn(2) atom to form distorted edge-sharing OCa3Mn2 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ca(5), one Ca(7), one Ti(1), and one Ti(3) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(6), one Ti(3), and one Mn(3) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Ca(2), one Ca(4), one Ca(6), one Mn(4), and one Mn(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Ca(3), one Ca(4), and one Ti(1) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), one Ti(2), and one Mn(3) atom. In the ninth O site, O(9) is bonded to one Ca(1), one Ca(3), one Ca(4), one Mn(1), and one Mn(4) atom to form distorted edge-sharing OCa3Mn2 trigonal bipyramids. In the tenth O site, O(10) is bonded to one Ca(1), one Ca(2), one Ca(3), one Mn(2), and one Mn(5) atom to form a mixture of distorted edge and corner-sharing OCa3Mn2 trigonal bipyramids. In the eleventh O site, O(11) is bonded in a distorted see-saw-like geometry to one Ca(5), one Ca(7), one Ti(2), and one Mn(3) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Ca(5), one Ca(6), one Ca(8), one Mn(1), and one Mn(4) atom. In the thirteenth O site, O(13) is bonded to one Ca(6), one Ca(7), one Ca(8), one Mn(2), and one Mn(5) atom to form a mixture of distorted edge and corner-sharing OCa3Mn2 trigonal bipyramids. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Ti(1), and one Mn(1) atom. In the fifteenth O site, O(15) is bonded in a distorted see-saw-like geometry to one Ca(2), one Ca(6), one Ti(2), and one Mn(2) atom. In the sixteenth O site, O(16) is bonded in a distorted see-saw-like geometry to one Ca(3), one Ca(7), one Ti(2), and one Mn(2) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(5), one Ti(3), and one Mn(4) atom. In the eighteenth O site, O(18) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(5), one Ca(6), one Mn(3), and one Mn(5) atom. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Ca(4), one Ca(8), one Ti(3), and one Mn(4) atom. In the twentieth O site, O(20) is bonded in a distorted see-saw-like geometry to one Ca(3), one Ca(7), one Mn(3), and one Mn(5) atom.
Ca8Ti3Mn5O20 crystallizes in the triclinic P1 space group. There are eight inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(10), one O(14), one O(17), one O(18), one O(2), one O(8), and one O(9) atom. The Ca(1)-O(10) bond length is 2.33 Å. The Ca(1)-O(14) bond length is 2.61 Å. The Ca(1)-O(17) bond length is 2.35 Å. The Ca(1)-O(18) bond length is 2.74 Å. The Ca(1)-O(2) bond length is 2.97 Å. The Ca(1)-O(8) bond length is 2.36 Å. The Ca(1)-O(9) bond length is 2.44 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(15), one O(3), one O(6), and one O(8) atom. The Ca(2)-O(10) bond length is 2.45 Å. The Ca(2)-O(14) bond length is 2.64 Å. The Ca(2)-O(15) bond length is 2.31 Å. The Ca(2)-O(3) bond length is 2.53 Å. The Ca(2)-O(6) bond length is 2.30 Å. The Ca(2)-O(8) bond length is 2.87 Å. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one O(10), one O(16), one O(20), one O(7), one O(8), and one O(9) atom. The Ca(3)-O(10) bond length is 2.43 Å. The Ca(3)-O(16) bond length is 2.28 Å. The Ca(3)-O(20) bond length is 2.27 Å. The Ca(3)-O(7) bond length is 2.29 Å. The Ca(3)-O(8) bond length is 2.88 Å. The Ca(3)-O(9) bond length is 2.38 Å. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to one O(1), one O(19), one O(3), one O(6), one O(7), and one O(9) atom. The Ca(4)-O(1) bond length is 2.74 Å. The Ca(4)-O(19) bond length is 2.48 Å. The Ca(4)-O(3) bond length is 2.24 Å. The Ca(4)-O(6) bond length is 2.39 Å. The Ca(4)-O(7) bond length is 2.38 Å. The Ca(4)-O(9) bond length is 2.49 Å. In the fifth Ca site, Ca(5) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(17), one O(18), one O(2), and one O(4) atom. The Ca(5)-O(11) bond length is 2.30 Å. The Ca(5)-O(12) bond length is 2.88 Å. The Ca(5)-O(17) bond length is 2.43 Å. The Ca(5)-O(18) bond length is 2.30 Å. The Ca(5)-O(2) bond length is 2.33 Å. The Ca(5)-O(4) bond length is 2.79 Å. In the sixth Ca site, Ca(6) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(15), one O(18), one O(5), and one O(6) atom. The Ca(6)-O(12) bond length is 2.48 Å. The Ca(6)-O(13) bond length is 2.39 Å. The Ca(6)-O(15) bond length is 2.29 Å. The Ca(6)-O(18) bond length is 2.42 Å. The Ca(6)-O(5) bond length is 2.45 Å. The Ca(6)-O(6) bond length is 2.59 Å. In the seventh Ca site, Ca(7) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(16), one O(2), one O(20), and one O(4) atom. The Ca(7)-O(11) bond length is 2.30 Å. The Ca(7)-O(13) bond length is 2.48 Å. The Ca(7)-O(16) bond length is 2.28 Å. The Ca(7)-O(2) bond length is 2.60 Å. The Ca(7)-O(20) bond length is 2.34 Å. The Ca(7)-O(4) bond length is 2.72 Å. In the eighth Ca site, Ca(8) is bonded in a 5-coordinate geometry to one O(1), one O(12), one O(13), one O(19), and one O(3) atom. The Ca(8)-O(1) bond length is 2.59 Å. The Ca(8)-O(12) bond length is 2.40 Å. The Ca(8)-O(13) bond length is 2.23 Å. The Ca(8)-O(19) bond length is 2.71 Å. The Ca(8)-O(3) bond length is 2.37 Å. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(14), one O(4), and one O(7) atom to form TiO4 tetrahedra that share  a cornercorner with one Ti(3)O4 tetrahedra,  a cornercorner with one Ti(2)O5 trigonal bipyramid, and  a cornercorner with one Mn(1)O5 trigonal bipyramid. The Ti(1)-O(1) bond length is 1.85 Å. The Ti(1)-O(14) bond length is 1.78 Å. The Ti(1)-O(4) bond length is 1.88 Å. The Ti(1)-O(7) bond length is 1.76 Å. In the second Ti site, Ti(2) is bonded to one O(1), one O(11), one O(15), one O(16), and one O(8) atom to form TiO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Ti(1)O4 tetrahedra, and corners with two equivalent Mn(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 30-32°. The Ti(2)-O(1) bond length is 1.95 Å. The Ti(2)-O(11) bond length is 1.92 Å. The Ti(2)-O(15) bond length is 1.98 Å. The Ti(2)-O(16) bond length is 1.91 Å. The Ti(2)-O(8) bond length is 1.89 Å. In the third Ti site, Ti(3) is bonded to one O(17), one O(19), one O(4), and one O(5) atom to form TiO4 tetrahedra that share corners with two equivalent Mn(4)O5 square pyramids,  a cornercorner with one Ti(1)O4 tetrahedra, and  a cornercorner with one Mn(3)O5 trigonal bipyramid. The Ti(3)-O(17) bond length is 1.85 Å. The Ti(3)-O(19) bond length is 1.83 Å. The Ti(3)-O(4) bond length is 1.91 Å. The Ti(3)-O(5) bond length is 1.82 Å. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(12), one O(14), one O(2), one O(3), and one O(9) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O5 square pyramids, and  a cornercorner with one Ti(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 28-29°. The Mn(1)-O(12) bond length is 2.00 Å. The Mn(1)-O(14) bond length is 2.10 Å. The Mn(1)-O(2) bond length is 1.93 Å. The Mn(1)-O(3) bond length is 1.98 Å. The Mn(1)-O(9) bond length is 2.04 Å. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(15), one O(16), one O(2), and one O(3) atom to form MnO6 octahedra that share corners with two equivalent Ti(2)O5 trigonal bipyramids, corners with two equivalent Mn(1)O5 trigonal bipyramids, and corners with two equivalent Mn(5)O5 trigonal bipyramids. The Mn(2)-O(10) bond length is 2.08 Å. The Mn(2)-O(13) bond length is 2.09 Å. The Mn(2)-O(15) bond length is 2.20 Å. The Mn(2)-O(16) bond length is 2.16 Å. The Mn(2)-O(2) bond length is 2.12 Å. The Mn(2)-O(3) bond length is 2.29 Å. In the third Mn site, Mn(3) is bonded to one O(11), one O(18), one O(20), one O(5), and one O(8) atom to form distorted MnO5 trigonal bipyramids that share  a cornercorner with one Ti(3)O4 tetrahedra, corners with two equivalent Ti(2)O5 trigonal bipyramids, and corners with two equivalent Mn(5)O5 trigonal bipyramids. The Mn(3)-O(11) bond length is 2.29 Å. The Mn(3)-O(18) bond length is 2.13 Å. The Mn(3)-O(20) bond length is 2.09 Å. The Mn(3)-O(5) bond length is 2.19 Å. The Mn(3)-O(8) bond length is 2.23 Å. In the fourth Mn site, Mn(4) is bonded to one O(12), one O(17), one O(19), one O(6), and one O(9) atom to form distorted MnO5 square pyramids that share corners with two equivalent Ti(3)O4 tetrahedra,  a cornercorner with one Mn(5)O5 trigonal bipyramid, and corners with two equivalent Mn(1)O5 trigonal bipyramids. The Mn(4)-O(12) bond length is 2.03 Å. The Mn(4)-O(17) bond length is 2.52 Å. The Mn(4)-O(19) bond length is 2.26 Å. The Mn(4)-O(6) bond length is 2.03 Å. The Mn(4)-O(9) bond length is 2.06 Å. In the fifth Mn site, Mn(5) is bonded to one O(10), one O(13), one O(18), one O(20), and one O(6) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Mn(4)O5 square pyramid, and corners with two equivalent Mn(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 26°. The Mn(5)-O(10) bond length is 1.94 Å. The Mn(5)-O(13) bond length is 1.95 Å. The Mn(5)-O(18) bond length is 2.01 Å. The Mn(5)-O(20) bond length is 2.00 Å. The Mn(5)-O(6) bond length is 2.09 Å. There are twenty inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Ca(4), one Ca(8), one Ti(1), and one Ti(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(5), one Ca(7), one Mn(1), and one Mn(2) atom. In the third O site, O(3) is bonded to one Ca(2), one Ca(4), one Ca(8), one Mn(1), and one Mn(2) atom to form distorted edge-sharing OCa3Mn2 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Ca(5), one Ca(7), one Ti(1), and one Ti(3) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(6), one Ti(3), and one Mn(3) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Ca(2), one Ca(4), one Ca(6), one Mn(4), and one Mn(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Ca(3), one Ca(4), and one Ti(1) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), one Ti(2), and one Mn(3) atom. In the ninth O site, O(9) is bonded to one Ca(1), one Ca(3), one Ca(4), one Mn(1), and one Mn(4) atom to form distorted edge-sharing OCa3Mn2 trigonal bipyramids. In the tenth O site, O(10) is bonded to one Ca(1), one Ca(2), one Ca(3), one Mn(2), and one Mn(5) atom to form a mixture of distorted edge and corner-sharing OCa3Mn2 trigonal bipyramids. In the eleventh O site, O(11) is bonded in a distorted see-saw-like geometry to one Ca(5), one Ca(7), one Ti(2), and one Mn(3) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Ca(5), one Ca(6), one Ca(8), one Mn(1), and one Mn(4) atom. In the thirteenth O site, O(13) is bonded to one Ca(6), one Ca(7), one Ca(8), one Mn(2), and one Mn(5) atom to form a mixture of distorted edge and corner-sharing OCa3Mn2 trigonal bipyramids. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Ti(1), and one Mn(1) atom. In the fifteenth O site, O(15) is bonded in a distorted see-saw-like geometry to one Ca(2), one Ca(6), one Ti(2), and one Mn(2) atom. In the sixteenth O site, O(16) is bonded in a distorted see-saw-like geometry to one Ca(3), one Ca(7), one Ti(2), and one Mn(2) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(5), one Ti(3), and one Mn(4) atom. In the eighteenth O site, O(18) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(5), one Ca(6), one Mn(3), and one Mn(5) atom. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Ca(4), one Ca(8), one Ti(3), and one Mn(4) atom. In the twentieth O site, O(20) is bonded in a distorted see-saw-like geometry to one Ca(3), one Ca(7), one Mn(3), and one Mn(5) atom.