Ca5Mn2(NiO6)2 crystallizes in the monoclinic C2 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(6), two equivalent O(4), and two equivalent O(5) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), two equivalent O(3), and two equivalent O(6) atoms. In the third Ca site, Ca(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. Mn(1) is bonded in an octahedral geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ni site, Ni(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(5), and two equivalent O(6) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Ni(2) atom to form a mixture of edge and corner-sharing OCa3MnNi square pyramids. In the second O site, O(2) is bonded to one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Ni(1) atom to form a mixture of distorted edge, corner, and face-sharing OCa3MnNi square pyramids. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ca(1), one Ca(3), two equivalent Ca(2), one Mn(1), and one Ni(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Ca(2), two equivalent Ca(1), one Mn(1), and one Ni(1) atom. In the fifth O site, O(5) is bonded to one Ca(2), two equivalent Ca(1), one Mn(1), and one Ni(2) atom to form a mixture of distorted edge, corner, and face-sharing OCa3MnNi trigonal bipyramids. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ca(1), one Ca(3), two equivalent Ca(2), one Mn(1), and one Ni(2) atom.
Ca5Mn2(NiO6)2 crystallizes in the monoclinic C2 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(6), two equivalent O(4), and two equivalent O(5) atoms. The Ca(1)-O(1) bond length is 2.51 Å. The Ca(1)-O(2) bond length is 2.73 Å. The Ca(1)-O(3) bond length is 2.48 Å. The Ca(1)-O(6) bond length is 2.35 Å. There is one shorter (2.41 Å) and one longer (2.78 Å) Ca(1)-O(4) bond length. There is one shorter (2.41 Å) and one longer (2.46 Å) Ca(1)-O(5) bond length. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), two equivalent O(3), and two equivalent O(6) atoms. The Ca(2)-O(1) bond length is 2.50 Å. The Ca(2)-O(2) bond length is 2.50 Å. The Ca(2)-O(4) bond length is 2.33 Å. The Ca(2)-O(5) bond length is 2.38 Å. There is one shorter (2.41 Å) and one longer (2.61 Å) Ca(2)-O(3) bond length. There is one shorter (2.42 Å) and one longer (2.73 Å) Ca(2)-O(6) bond length. In the third Ca site, Ca(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. Both Ca(3)-O(1) bond lengths are 2.33 Å. Both Ca(3)-O(2) bond lengths are 2.41 Å. Both Ca(3)-O(3) bond lengths are 2.77 Å. Both Ca(3)-O(6) bond lengths are 2.43 Å. Mn(1) is bonded in an octahedral geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Mn(1)-O(1) bond length is 1.89 Å. The Mn(1)-O(2) bond length is 1.91 Å. The Mn(1)-O(3) bond length is 1.96 Å. The Mn(1)-O(4) bond length is 1.93 Å. The Mn(1)-O(5) bond length is 1.90 Å. The Mn(1)-O(6) bond length is 1.92 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both Ni(1)-O(2) bond lengths are 2.04 Å. Both Ni(1)-O(3) bond lengths are 2.06 Å. Both Ni(1)-O(4) bond lengths are 1.96 Å. In the second Ni site, Ni(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(5), and two equivalent O(6) atoms. Both Ni(2)-O(1) bond lengths are 2.12 Å. Both Ni(2)-O(5) bond lengths are 2.13 Å. Both Ni(2)-O(6) bond lengths are 2.17 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Ni(2) atom to form a mixture of edge and corner-sharing OCa3MnNi square pyramids. In the second O site, O(2) is bonded to one Ca(1), one Ca(2), one Ca(3), one Mn(1), and one Ni(1) atom to form a mixture of distorted edge, corner, and face-sharing OCa3MnNi square pyramids. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Ca(1), one Ca(3), two equivalent Ca(2), one Mn(1), and one Ni(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Ca(2), two equivalent Ca(1), one Mn(1), and one Ni(1) atom. In the fifth O site, O(5) is bonded to one Ca(2), two equivalent Ca(1), one Mn(1), and one Ni(2) atom to form a mixture of distorted edge, corner, and face-sharing OCa3MnNi trigonal bipyramids. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ca(1), one Ca(3), two equivalent Ca(2), one Mn(1), and one Ni(2) atom.