Ca2NiAlO5 crystallizes in the orthorhombic Ima2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. Ni(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. Al(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and two equivalent Al(1) atoms to form distorted OCa2Al2 tetrahedra that share corners with eight equivalent O(3)Ca4Ni2 octahedra and corners with two equivalent O(1)Ca2Al2 tetrahedra. The corner-sharing octahedral tilt angles range from 15-88°. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Ni(1), and one Al(1) atom. In the third O site, O(3) is bonded to four equivalent Ca(1) and two equivalent Ni(1) atoms to form distorted OCa4Ni2 octahedra that share corners with two equivalent O(3)Ca4Ni2 octahedra, corners with four equivalent O(1)Ca2Al2 tetrahedra, edges with two equivalent O(3)Ca4Ni2 octahedra, and faces with four equivalent O(3)Ca4Ni2 octahedra. The corner-sharing octahedral tilt angles are 3°.
Ca2NiAlO5 crystallizes in the orthorhombic Ima2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. The Ca(1)-O(1) bond length is 2.37 Å. There are a spread of Ca(1)-O(2) bond distances ranging from 2.30-2.88 Å. There are a spread of Ca(1)-O(3) bond distances ranging from 2.46-2.57 Å. Ni(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. Both Ni(1)-O(2) bond lengths are 2.17 Å. There are two shorter (1.94 Å) and two longer (1.95 Å) Ni(1)-O(3) bond lengths. Al(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There is one shorter (1.79 Å) and one longer (1.80 Å) Al(1)-O(1) bond length. Both Al(1)-O(2) bond lengths are 1.75 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and two equivalent Al(1) atoms to form distorted OCa2Al2 tetrahedra that share corners with eight equivalent O(3)Ca4Ni2 octahedra and corners with two equivalent O(1)Ca2Al2 tetrahedra. The corner-sharing octahedral tilt angles range from 15-88°. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Ni(1), and one Al(1) atom. In the third O site, O(3) is bonded to four equivalent Ca(1) and two equivalent Ni(1) atoms to form distorted OCa4Ni2 octahedra that share corners with two equivalent O(3)Ca4Ni2 octahedra, corners with four equivalent O(1)Ca2Al2 tetrahedra, edges with two equivalent O(3)Ca4Ni2 octahedra, and faces with four equivalent O(3)Ca4Ni2 octahedra. The corner-sharing octahedral tilt angles are 3°.