Ca2Ni9O13 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(6) and four equivalent O(7) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the second Ni site, Ni(2) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the third Ni site, Ni(3) is bonded to one O(5), two equivalent O(6), and three equivalent O(7) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the fourth Ni site, Ni(4) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-47°. In the fifth Ni site, Ni(5) is bonded to one O(2), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-47°. There are seven inequivalent O sites. In the first O site, O(7) is bonded to one Ni(5), two equivalent Ni(1), and three equivalent Ni(3) atoms to form ONi6 octahedra that share corners with two equivalent O(7)Ni6 octahedra, corners with two equivalent O(6)Ni5 square pyramids,  a cornercorner with one O(2)Ca2Ni2 tetrahedra,  a cornercorner with one O(5)Ca2Ni3 trigonal bipyramid, edges with five equivalent O(7)Ni6 octahedra, edges with five equivalent O(6)Ni5 square pyramids, and edges with two equivalent O(5)Ca2Ni3 trigonal bipyramids. The corner-sharing octahedra are not tilted. In the second O site, O(1) is bonded to two equivalent Ni(4) and four equivalent Ni(2) atoms to form ONi6 octahedra that share corners with four equivalent O(3)Ni5 square pyramids, corners with two equivalent O(2)Ca2Ni2 tetrahedra, edges with two equivalent O(1)Ni6 octahedra, edges with six equivalent O(3)Ni5 square pyramids, and edges with four equivalent O(4)Ca2Ni3 trigonal bipyramids. In the third O site, O(2) is bonded to two equivalent Ca(1), one Ni(4), and one Ni(5) atom to form distorted OCa2Ni2 tetrahedra that share  a cornercorner with one O(1)Ni6 octahedra,  a cornercorner with one O(7)Ni6 octahedra, corners with two equivalent O(3)Ni5 square pyramids, corners with two equivalent O(6)Ni5 square pyramids, corners with two equivalent O(2)Ca2Ni2 tetrahedra, corners with four equivalent O(4)Ca2Ni3 trigonal bipyramids, corners with four equivalent O(5)Ca2Ni3 trigonal bipyramids,  an edgeedge with one O(4)Ca2Ni3 trigonal bipyramid, and  an edgeedge with one O(5)Ca2Ni3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 1-2°. In the fourth O site, O(3) is bonded to two equivalent Ni(4) and three equivalent Ni(2) atoms to form distorted ONi5 square pyramids that share corners with two equivalent O(1)Ni6 octahedra, corners with two equivalent O(2)Ca2Ni2 tetrahedra, corners with five equivalent O(4)Ca2Ni3 trigonal bipyramids, edges with three equivalent O(1)Ni6 octahedra, edges with four equivalent O(3)Ni5 square pyramids, and  an edgeedge with one O(4)Ca2Ni3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 3°. In the fifth O site, O(4) is bonded to two equivalent Ca(1), one Ni(2), and two equivalent Ni(4) atoms to form distorted OCa2Ni3 trigonal bipyramids that share corners with five equivalent O(3)Ni5 square pyramids, corners with four equivalent O(2)Ca2Ni2 tetrahedra, corners with two equivalent O(5)Ca2Ni3 trigonal bipyramids, edges with two equivalent O(1)Ni6 octahedra,  an edgeedge with one O(3)Ni5 square pyramid,  an edgeedge with one O(2)Ca2Ni2 tetrahedra,  an edgeedge with one O(5)Ca2Ni3 trigonal bipyramid, and edges with two equivalent O(4)Ca2Ni3 trigonal bipyramids. In the sixth O site, O(5) is bonded to two equivalent Ca(1), one Ni(3), and two equivalent Ni(5) atoms to form distorted OCa2Ni3 trigonal bipyramids that share  a cornercorner with one O(7)Ni6 octahedra, corners with four equivalent O(6)Ni5 square pyramids, corners with four equivalent O(2)Ca2Ni2 tetrahedra, corners with two equivalent O(4)Ca2Ni3 trigonal bipyramids, edges with two equivalent O(7)Ni6 octahedra,  an edgeedge with one O(6)Ni5 square pyramid,  an edgeedge with one O(2)Ca2Ni2 tetrahedra,  an edgeedge with one O(4)Ca2Ni3 trigonal bipyramid, and edges with two equivalent O(5)Ca2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the seventh O site, O(6) is bonded to one Ni(1), two equivalent Ni(3), and two equivalent Ni(5) atoms to form distorted ONi5 square pyramids that share corners with two equivalent O(7)Ni6 octahedra,  a cornercorner with one O(6)Ni5 square pyramid, corners with two equivalent O(2)Ca2Ni2 tetrahedra, corners with four equivalent O(5)Ca2Ni3 trigonal bipyramids, edges with five equivalent O(7)Ni6 octahedra, edges with two equivalent O(6)Ni5 square pyramids, and  an edgeedge with one O(5)Ca2Ni3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 4°.
Ca2Ni9O13 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. Both Ca(1)-O(2) bond lengths are 2.28 Å. Both Ca(1)-O(4) bond lengths are 2.38 Å. Both Ca(1)-O(5) bond lengths are 2.39 Å. There are five inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(6) and four equivalent O(7) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles are 4°. Both Ni(1)-O(6) bond lengths are 2.04 Å. All Ni(1)-O(7) bond lengths are 2.12 Å. In the second Ni site, Ni(2) is bonded to one O(4), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. The Ni(2)-O(4) bond length is 1.90 Å. Both Ni(2)-O(1) bond lengths are 2.12 Å. There is one shorter (1.97 Å) and two longer (2.09 Å) Ni(2)-O(3) bond lengths. In the third Ni site, Ni(3) is bonded to one O(5), two equivalent O(6), and three equivalent O(7) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. The Ni(3)-O(5) bond length is 1.92 Å. Both Ni(3)-O(6) bond lengths are 2.10 Å. There is one shorter (2.03 Å) and two longer (2.13 Å) Ni(3)-O(7) bond lengths. In the fourth Ni site, Ni(4) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-47°. The Ni(4)-O(1) bond length is 2.16 Å. The Ni(4)-O(2) bond length is 1.95 Å. Both Ni(4)-O(3) bond lengths are 2.16 Å. Both Ni(4)-O(4) bond lengths are 2.03 Å. In the fifth Ni site, Ni(5) is bonded to one O(2), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-47°. The Ni(5)-O(2) bond length is 1.96 Å. The Ni(5)-O(7) bond length is 2.28 Å. Both Ni(5)-O(5) bond lengths are 2.02 Å. Both Ni(5)-O(6) bond lengths are 2.13 Å. There are seven inequivalent O sites. In the first O site, O(7) is bonded to one Ni(5), two equivalent Ni(1), and three equivalent Ni(3) atoms to form ONi6 octahedra that share corners with two equivalent O(7)Ni6 octahedra, corners with two equivalent O(6)Ni5 square pyramids,  a cornercorner with one O(2)Ca2Ni2 tetrahedra,  a cornercorner with one O(5)Ca2Ni3 trigonal bipyramid, edges with five equivalent O(7)Ni6 octahedra, edges with five equivalent O(6)Ni5 square pyramids, and edges with two equivalent O(5)Ca2Ni3 trigonal bipyramids. The corner-sharing octahedra are not tilted. In the second O site, O(1) is bonded to two equivalent Ni(4) and four equivalent Ni(2) atoms to form ONi6 octahedra that share corners with four equivalent O(3)Ni5 square pyramids, corners with two equivalent O(2)Ca2Ni2 tetrahedra, edges with two equivalent O(1)Ni6 octahedra, edges with six equivalent O(3)Ni5 square pyramids, and edges with four equivalent O(4)Ca2Ni3 trigonal bipyramids. In the third O site, O(2) is bonded to two equivalent Ca(1), one Ni(4), and one Ni(5) atom to form distorted OCa2Ni2 tetrahedra that share  a cornercorner with one O(1)Ni6 octahedra,  a cornercorner with one O(7)Ni6 octahedra, corners with two equivalent O(3)Ni5 square pyramids, corners with two equivalent O(6)Ni5 square pyramids, corners with two equivalent O(2)Ca2Ni2 tetrahedra, corners with four equivalent O(4)Ca2Ni3 trigonal bipyramids, corners with four equivalent O(5)Ca2Ni3 trigonal bipyramids,  an edgeedge with one O(4)Ca2Ni3 trigonal bipyramid, and  an edgeedge with one O(5)Ca2Ni3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 1-2°. In the fourth O site, O(3) is bonded to two equivalent Ni(4) and three equivalent Ni(2) atoms to form distorted ONi5 square pyramids that share corners with two equivalent O(1)Ni6 octahedra, corners with two equivalent O(2)Ca2Ni2 tetrahedra, corners with five equivalent O(4)Ca2Ni3 trigonal bipyramids, edges with three equivalent O(1)Ni6 octahedra, edges with four equivalent O(3)Ni5 square pyramids, and  an edgeedge with one O(4)Ca2Ni3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 3°. In the fifth O site, O(4) is bonded to two equivalent Ca(1), one Ni(2), and two equivalent Ni(4) atoms to form distorted OCa2Ni3 trigonal bipyramids that share corners with five equivalent O(3)Ni5 square pyramids, corners with four equivalent O(2)Ca2Ni2 tetrahedra, corners with two equivalent O(5)Ca2Ni3 trigonal bipyramids, edges with two equivalent O(1)Ni6 octahedra,  an edgeedge with one O(3)Ni5 square pyramid,  an edgeedge with one O(2)Ca2Ni2 tetrahedra,  an edgeedge with one O(5)Ca2Ni3 trigonal bipyramid, and edges with two equivalent O(4)Ca2Ni3 trigonal bipyramids. In the sixth O site, O(5) is bonded to two equivalent Ca(1), one Ni(3), and two equivalent Ni(5) atoms to form distorted OCa2Ni3 trigonal bipyramids that share  a cornercorner with one O(7)Ni6 octahedra, corners with four equivalent O(6)Ni5 square pyramids, corners with four equivalent O(2)Ca2Ni2 tetrahedra, corners with two equivalent O(4)Ca2Ni3 trigonal bipyramids, edges with two equivalent O(7)Ni6 octahedra,  an edgeedge with one O(6)Ni5 square pyramid,  an edgeedge with one O(2)Ca2Ni2 tetrahedra,  an edgeedge with one O(4)Ca2Ni3 trigonal bipyramid, and edges with two equivalent O(5)Ca2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the seventh O site, O(6) is bonded to one Ni(1), two equivalent Ni(3), and two equivalent Ni(5) atoms to form distorted ONi5 square pyramids that share corners with two equivalent O(7)Ni6 octahedra,  a cornercorner with one O(6)Ni5 square pyramid, corners with two equivalent O(2)Ca2Ni2 tetrahedra, corners with four equivalent O(5)Ca2Ni3 trigonal bipyramids, edges with five equivalent O(7)Ni6 octahedra, edges with two equivalent O(6)Ni5 square pyramids, and  an edgeedge with one O(5)Ca2Ni3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 4°.