Ca2Mn2O5 crystallizes in the triclinic P1 space group. There are eight inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(16), one O(17), one O(18), one O(3), 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(1), one O(10), one O(13), one O(18), one O(2), and one O(5) atom. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one O(1), one O(13), one O(15), one O(19), and one O(20) atom. In the fourth Ca site, Ca(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(14), one O(20), one O(3), one O(6), and one O(8) atom. In the fifth Ca site, Ca(5) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(19), one O(4), one O(7), and one O(9) atom. In the sixth Ca site, Ca(6) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(20), one O(5), one O(6), and one O(8) atom. In the seventh Ca site, Ca(7) is bonded in a 6-coordinate geometry to one O(16), one O(17), one O(2), one O(4), one O(7), and one O(9) atom. In the eighth Ca site, Ca(8) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(16), one O(18), one O(3), one O(5), one O(6), and one O(8) atom. There are eight inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(11), one O(12), one O(14), one O(16), one O(8), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(3)O5 square pyramids, and corners with two equivalent Mn(7)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 20-23°. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(15), and one O(7) atom to form MnO4 tetrahedra that share corners with two equivalent Mn(4)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, and  a cornercorner with one Mn(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-31°. In the third Mn site, Mn(3) is bonded to one O(12), one O(17), one O(19), one O(7), and one O(9) atom to form MnO5 square pyramids that share corners with two equivalent Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O4 tetrahedra, and corners with two equivalent Mn(5)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 25-29°. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(11), one O(13), one O(18), one O(20), and one O(8) atom to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra, and corners with two equivalent Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-28°. In the fifth Mn site, Mn(5) is bonded to one O(17), one O(19), one O(2), and one O(4) atom to form MnO4 trigonal pyramids that share corners with two equivalent Mn(3)O5 square pyramids,  a cornercorner with one Mn(8)O4 tetrahedra, and  a cornercorner with one Mn(7)O5 trigonal bipyramid. In the sixth Mn site, Mn(6) is bonded to one O(1), one O(18), one O(20), one O(3), one O(5), and one O(6) atom to form MnO6 octahedra that share corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(8)O4 tetrahedra, and corners with two equivalent Mn(7)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 22-28°. In the seventh Mn site, Mn(7) is bonded to one O(14), one O(16), one O(3), one O(4), and one O(6) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra, and  a cornercorner with one Mn(5)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 25-36°. In the eighth Mn site, Mn(8) is bonded to one O(1), one O(15), one O(2), and one O(5) atom to form distorted MnO4 tetrahedra that share corners with two equivalent Mn(6)O6 octahedra,  a cornercorner with one Mn(2)O4 tetrahedra, and  a cornercorner with one Mn(5)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 27-39°. There are twenty inequivalent O sites. In the first O site, O(1) is bonded to one Ca(2), one Ca(3), one Mn(6), and one Mn(8) atom to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent O(13)Ca2Mn2 tetrahedra,  a cornercorner with one O(19)Ca2Mn2 trigonal pyramid, and  an edgeedge with one O(20)Ca3Mn2 square pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(7), one Mn(5), and one Mn(8) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(8), one Mn(6), and one Mn(7) atom. In the fourth O site, O(4) is bonded to one Ca(5), one Ca(7), one Mn(5), and one Mn(7) atom to form distorted OCa2Mn2 trigonal pyramids that share  an edgeedge with one O(16)Ca3Mn2 trigonal bipyramid and  an edgeedge with one O(19)Ca2Mn2 trigonal pyramid. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Ca(2), one Ca(6), one Ca(8), one Mn(6), and one Mn(8) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Ca(4), one Ca(6), one Ca(8), one Mn(6), and one Mn(7) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Ca(5), one Ca(7), one Mn(2), and one Mn(3) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(6), one Ca(8), one Mn(1), and one Mn(4) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(5), one Ca(7), one Mn(1), and one Mn(3) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(6), one Ca(8), one Mn(2), and one Mn(4) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(8), one Mn(1), and one Mn(4) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(5), one Mn(1), and one Mn(3) atom. In the thirteenth O site, O(13) is bonded to one Ca(2), one Ca(3), one Mn(2), and one Mn(4) atom to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent O(1)Ca2Mn2 tetrahedra,  a cornercorner with one O(19)Ca2Mn2 trigonal pyramid, and  an edgeedge with one O(20)Ca3Mn2 square pyramid. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ca(4), one Ca(6), one Mn(1), and one Mn(7) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Ca(3), one Ca(5), one Mn(2), and one Mn(8) atom. In the sixteenth O site, O(16) is bonded to one Ca(1), one Ca(7), one Ca(8), one Mn(1), and one Mn(7) atom to form distorted edge-sharing OCa3Mn2 trigonal bipyramids. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ca(7), one Mn(3), and one Mn(5) atom. In the eighteenth O site, O(18) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(2), one Ca(8), one Mn(4), and one Mn(6) atom. In the nineteenth O site, O(19) is bonded to one Ca(3), one Ca(5), one Mn(3), and one Mn(5) atom to form distorted OCa2Mn2 trigonal pyramids that share  a cornercorner with one O(20)Ca3Mn2 square pyramid,  a cornercorner with one O(1)Ca2Mn2 tetrahedra,  a cornercorner with one O(13)Ca2Mn2 tetrahedra, and  an edgeedge with one O(4)Ca2Mn2 trigonal pyramid. In the twentieth O site, O(20) is bonded to one Ca(3), one Ca(4), one Ca(6), one Mn(4), and one Mn(6) atom to form a mixture of distorted corner and edge-sharing OCa3Mn2 square pyramids.
Ca2Mn2O5 crystallizes in the triclinic P1 space group. There are eight inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(16), one O(17), one O(18), one O(3), one O(8), and one O(9) atom. The Ca(1)-O(11) bond length is 2.29 Å. The Ca(1)-O(12) bond length is 2.72 Å. The Ca(1)-O(16) bond length is 2.35 Å. The Ca(1)-O(17) bond length is 2.41 Å. The Ca(1)-O(18) bond length is 2.76 Å. The Ca(1)-O(3) bond length is 2.35 Å. The Ca(1)-O(8) bond length is 2.94 Å. The Ca(1)-O(9) bond length is 2.85 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(18), one O(2), and one O(5) atom. The Ca(2)-O(1) bond length is 2.33 Å. The Ca(2)-O(10) bond length is 2.44 Å. The Ca(2)-O(13) bond length is 2.40 Å. The Ca(2)-O(18) bond length is 2.41 Å. The Ca(2)-O(2) bond length is 2.28 Å. The Ca(2)-O(5) bond length is 2.44 Å. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one O(1), one O(13), one O(15), one O(19), and one O(20) atom. The Ca(3)-O(1) bond length is 2.29 Å. The Ca(3)-O(13) bond length is 2.30 Å. The Ca(3)-O(15) bond length is 2.32 Å. The Ca(3)-O(19) bond length is 2.42 Å. The Ca(3)-O(20) bond length is 2.49 Å. In the fourth Ca site, Ca(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(14), one O(20), one O(3), one O(6), and one O(8) atom. The Ca(4)-O(11) bond length is 2.53 Å. The Ca(4)-O(12) bond length is 2.39 Å. The Ca(4)-O(14) bond length is 2.34 Å. The Ca(4)-O(20) bond length is 2.41 Å. The Ca(4)-O(3) bond length is 2.53 Å. The Ca(4)-O(6) bond length is 2.64 Å. The Ca(4)-O(8) bond length is 2.51 Å. In the fifth Ca site, Ca(5) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(19), one O(4), one O(7), and one O(9) atom. The Ca(5)-O(12) bond length is 2.49 Å. The Ca(5)-O(15) bond length is 2.58 Å. The Ca(5)-O(19) bond length is 2.47 Å. The Ca(5)-O(4) bond length is 2.30 Å. The Ca(5)-O(7) bond length is 2.43 Å. The Ca(5)-O(9) bond length is 2.34 Å. In the sixth Ca site, Ca(6) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(20), one O(5), one O(6), and one O(8) atom. The Ca(6)-O(10) bond length is 2.83 Å. The Ca(6)-O(14) bond length is 2.48 Å. The Ca(6)-O(20) bond length is 2.34 Å. The Ca(6)-O(5) bond length is 2.73 Å. The Ca(6)-O(6) bond length is 2.29 Å. The Ca(6)-O(8) bond length is 2.35 Å. In the seventh Ca site, Ca(7) is bonded in a 6-coordinate geometry to one O(16), one O(17), one O(2), one O(4), one O(7), and one O(9) atom. The Ca(7)-O(16) bond length is 2.48 Å. The Ca(7)-O(17) bond length is 2.33 Å. The Ca(7)-O(2) bond length is 2.41 Å. The Ca(7)-O(4) bond length is 2.30 Å. The Ca(7)-O(7) bond length is 2.37 Å. The Ca(7)-O(9) bond length is 2.37 Å. In the eighth Ca site, Ca(8) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(16), one O(18), one O(3), one O(5), one O(6), and one O(8) atom. The Ca(8)-O(10) bond length is 2.47 Å. The Ca(8)-O(11) bond length is 2.54 Å. The Ca(8)-O(16) bond length is 2.46 Å. The Ca(8)-O(18) bond length is 2.38 Å. The Ca(8)-O(3) bond length is 2.88 Å. The Ca(8)-O(5) bond length is 2.40 Å. The Ca(8)-O(6) bond length is 2.66 Å. The Ca(8)-O(8) bond length is 2.57 Å. There are eight inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(11), one O(12), one O(14), one O(16), one O(8), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(3)O5 square pyramids, and corners with two equivalent Mn(7)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 20-23°. The Mn(1)-O(11) bond length is 2.00 Å. The Mn(1)-O(12) bond length is 1.94 Å. The Mn(1)-O(14) bond length is 1.90 Å. The Mn(1)-O(16) bond length is 2.05 Å. The Mn(1)-O(8) bond length is 1.96 Å. The Mn(1)-O(9) bond length is 2.08 Å. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(15), and one O(7) atom to form MnO4 tetrahedra that share corners with two equivalent Mn(4)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, and  a cornercorner with one Mn(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-31°. The Mn(2)-O(10) bond length is 1.89 Å. The Mn(2)-O(13) bond length is 1.93 Å. The Mn(2)-O(15) bond length is 1.92 Å. The Mn(2)-O(7) bond length is 1.89 Å. In the third Mn site, Mn(3) is bonded to one O(12), one O(17), one O(19), one O(7), and one O(9) atom to form MnO5 square pyramids that share corners with two equivalent Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O4 tetrahedra, and corners with two equivalent Mn(5)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 25-29°. The Mn(3)-O(12) bond length is 2.08 Å. The Mn(3)-O(17) bond length is 2.05 Å. The Mn(3)-O(19) bond length is 2.02 Å. The Mn(3)-O(7) bond length is 1.96 Å. The Mn(3)-O(9) bond length is 1.94 Å. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(11), one O(13), one O(18), one O(20), and one O(8) atom to form MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra, and corners with two equivalent Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-28°. The Mn(4)-O(10) bond length is 2.19 Å. The Mn(4)-O(11) bond length is 1.98 Å. The Mn(4)-O(13) bond length is 1.96 Å. The Mn(4)-O(18) bond length is 1.94 Å. The Mn(4)-O(20) bond length is 1.98 Å. The Mn(4)-O(8) bond length is 2.07 Å. In the fifth Mn site, Mn(5) is bonded to one O(17), one O(19), one O(2), and one O(4) atom to form MnO4 trigonal pyramids that share corners with two equivalent Mn(3)O5 square pyramids,  a cornercorner with one Mn(8)O4 tetrahedra, and  a cornercorner with one Mn(7)O5 trigonal bipyramid. The Mn(5)-O(17) bond length is 2.03 Å. The Mn(5)-O(19) bond length is 2.09 Å. The Mn(5)-O(2) bond length is 2.11 Å. The Mn(5)-O(4) bond length is 2.08 Å. In the sixth Mn site, Mn(6) is bonded to one O(1), one O(18), one O(20), one O(3), one O(5), and one O(6) atom to form MnO6 octahedra that share corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(8)O4 tetrahedra, and corners with two equivalent Mn(7)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 22-28°. The Mn(6)-O(1) bond length is 2.14 Å. The Mn(6)-O(18) bond length is 1.91 Å. The Mn(6)-O(20) bond length is 2.00 Å. The Mn(6)-O(3) bond length is 1.94 Å. The Mn(6)-O(5) bond length is 1.98 Å. The Mn(6)-O(6) bond length is 1.99 Å. In the seventh Mn site, Mn(7) is bonded to one O(14), one O(16), one O(3), one O(4), and one O(6) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra, and  a cornercorner with one Mn(5)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 25-36°. The Mn(7)-O(14) bond length is 1.93 Å. The Mn(7)-O(16) bond length is 1.99 Å. The Mn(7)-O(3) bond length is 2.06 Å. The Mn(7)-O(4) bond length is 1.90 Å. The Mn(7)-O(6) bond length is 1.98 Å. In the eighth Mn site, Mn(8) is bonded to one O(1), one O(15), one O(2), and one O(5) atom to form distorted MnO4 tetrahedra that share corners with two equivalent Mn(6)O6 octahedra,  a cornercorner with one Mn(2)O4 tetrahedra, and  a cornercorner with one Mn(5)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 27-39°. The Mn(8)-O(1) bond length is 1.97 Å. The Mn(8)-O(15) bond length is 2.02 Å. The Mn(8)-O(2) bond length is 1.97 Å. The Mn(8)-O(5) bond length is 2.02 Å. There are twenty inequivalent O sites. In the first O site, O(1) is bonded to one Ca(2), one Ca(3), one Mn(6), and one Mn(8) atom to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent O(13)Ca2Mn2 tetrahedra,  a cornercorner with one O(19)Ca2Mn2 trigonal pyramid, and  an edgeedge with one O(20)Ca3Mn2 square pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(7), one Mn(5), and one Mn(8) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(8), one Mn(6), and one Mn(7) atom. In the fourth O site, O(4) is bonded to one Ca(5), one Ca(7), one Mn(5), and one Mn(7) atom to form distorted OCa2Mn2 trigonal pyramids that share  an edgeedge with one O(16)Ca3Mn2 trigonal bipyramid and  an edgeedge with one O(19)Ca2Mn2 trigonal pyramid. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Ca(2), one Ca(6), one Ca(8), one Mn(6), and one Mn(8) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Ca(4), one Ca(6), one Ca(8), one Mn(6), and one Mn(7) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Ca(5), one Ca(7), one Mn(2), and one Mn(3) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(6), one Ca(8), one Mn(1), and one Mn(4) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(5), one Ca(7), one Mn(1), and one Mn(3) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(6), one Ca(8), one Mn(2), and one Mn(4) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(8), one Mn(1), and one Mn(4) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(4), one Ca(5), one Mn(1), and one Mn(3) atom. In the thirteenth O site, O(13) is bonded to one Ca(2), one Ca(3), one Mn(2), and one Mn(4) atom to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent O(1)Ca2Mn2 tetrahedra,  a cornercorner with one O(19)Ca2Mn2 trigonal pyramid, and  an edgeedge with one O(20)Ca3Mn2 square pyramid. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ca(4), one Ca(6), one Mn(1), and one Mn(7) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Ca(3), one Ca(5), one Mn(2), and one Mn(8) atom. In the sixteenth O site, O(16) is bonded to one Ca(1), one Ca(7), one Ca(8), one Mn(1), and one Mn(7) atom to form distorted edge-sharing OCa3Mn2 trigonal bipyramids. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ca(7), one Mn(3), and one Mn(5) atom. In the eighteenth O site, O(18) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(2), one Ca(8), one Mn(4), and one Mn(6) atom. In the nineteenth O site, O(19) is bonded to one Ca(3), one Ca(5), one Mn(3), and one Mn(5) atom to form distorted OCa2Mn2 trigonal pyramids that share  a cornercorner with one O(20)Ca3Mn2 square pyramid,  a cornercorner with one O(1)Ca2Mn2 tetrahedra,  a cornercorner with one O(13)Ca2Mn2 tetrahedra, and  an edgeedge with one O(4)Ca2Mn2 trigonal pyramid. In the twentieth O site, O(20) is bonded to one Ca(3), one Ca(4), one Ca(6), one Mn(4), and one Mn(6) atom to form a mixture of distorted corner and edge-sharing OCa3Mn2 square pyramids.