Ca2Ni2O5 crystallizes in the orthorhombic Pbam space group. Ca(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Ni(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Ni(1) atoms to form edge-sharing OCa4Ni2 octahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms.
Ca2Ni2O5 crystallizes in the orthorhombic Pbam space group. Ca(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Both Ca(1)-O(1) bond lengths are 2.54 Å. There are two shorter (2.40 Å) and two longer (2.90 Å) Ca(1)-O(2) bond lengths. There are a spread of Ca(1)-O(3) bond distances ranging from 2.43-2.78 Å. Ni(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. The Ni(1)-O(1) bond length is 1.95 Å. There is one shorter (1.87 Å) and one longer (1.96 Å) Ni(1)-O(2) bond length. Both Ni(1)-O(3) bond lengths are 1.91 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Ni(1) atoms to form edge-sharing OCa4Ni2 octahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms.