NaNi3O5 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 4-51°. In the second Ni site, Ni(2) is bonded to one O(5), two equivalent O(4), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Ni site, Ni(3) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 4-51°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ni(3), two equivalent Ni(1), and three equivalent Ni(2) atoms to form ONi6 octahedra that share corners with two equivalent O(4)Na2Ni3 square pyramids,  a cornercorner with one O(5)Na2Ni3 trigonal bipyramid, corners with three equivalent O(3)NaNi3 trigonal pyramids, edges with four equivalent O(1)Ni6 octahedra, edges with three equivalent O(4)Na2Ni3 square pyramids, edges with two equivalent O(5)Na2Ni3 trigonal bipyramids, and  an edgeedge with one O(3)NaNi3 trigonal pyramid. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Ni(1), and two equivalent Ni(3) atoms. In the third O site, O(3) is bonded to one Na(1), one Ni(3), and two equivalent Ni(1) atoms to form distorted ONaNi3 trigonal pyramids that share corners with three equivalent O(1)Ni6 octahedra, corners with four equivalent O(5)Na2Ni3 trigonal bipyramids, corners with two equivalent O(3)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Ni6 octahedra, and edges with two equivalent O(4)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 6-14°. In the fourth O site, O(4) is bonded to two equivalent Na(1), one Ni(1), and two equivalent Ni(2) atoms to form distorted ONa2Ni3 square pyramids that share corners with two equivalent O(1)Ni6 octahedra, corners with four equivalent O(5)Na2Ni3 trigonal bipyramids, edges with three equivalent O(1)Ni6 octahedra, edges with two equivalent O(4)Na2Ni3 square pyramids,  an edgeedge with one O(5)Na2Ni3 trigonal bipyramid, and edges with two equivalent O(3)NaNi3 trigonal pyramids. The corner-sharing octahedral tilt angles are 11°. In the fifth O site, O(5) is bonded to two equivalent Na(1), one Ni(2), and two equivalent Ni(3) atoms to form distorted ONa2Ni3 trigonal bipyramids that share  a cornercorner with one O(1)Ni6 octahedra, corners with four equivalent O(4)Na2Ni3 square pyramids, corners with four equivalent O(3)NaNi3 trigonal pyramids, edges with two equivalent O(1)Ni6 octahedra,  an edgeedge with one O(4)Na2Ni3 square pyramid, and edges with two equivalent O(5)Na2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 13°.
NaNi3O5 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. The Na(1)-O(3) bond length is 2.46 Å. Both Na(1)-O(2) bond lengths are 2.53 Å. Both Na(1)-O(4) bond lengths are 2.52 Å. Both Na(1)-O(5) bond lengths are 2.54 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 4-51°. The Ni(1)-O(2) bond length is 1.90 Å. The Ni(1)-O(4) bond length is 1.91 Å. Both Ni(1)-O(1) bond lengths are 2.05 Å. Both Ni(1)-O(3) bond lengths are 1.89 Å. In the second Ni site, Ni(2) is bonded to one O(5), two equivalent O(4), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles are 4°. The Ni(2)-O(5) bond length is 2.02 Å. Both Ni(2)-O(4) bond lengths are 1.98 Å. There is one shorter (2.14 Å) and two longer (2.15 Å) Ni(2)-O(1) bond lengths. In the third Ni site, Ni(3) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 4-51°. The Ni(3)-O(1) bond length is 2.12 Å. The Ni(3)-O(3) bond length is 1.94 Å. Both Ni(3)-O(2) bond lengths are 1.93 Å. Both Ni(3)-O(5) bond lengths are 1.94 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Ni(3), two equivalent Ni(1), and three equivalent Ni(2) atoms to form ONi6 octahedra that share corners with two equivalent O(4)Na2Ni3 square pyramids,  a cornercorner with one O(5)Na2Ni3 trigonal bipyramid, corners with three equivalent O(3)NaNi3 trigonal pyramids, edges with four equivalent O(1)Ni6 octahedra, edges with three equivalent O(4)Na2Ni3 square pyramids, edges with two equivalent O(5)Na2Ni3 trigonal bipyramids, and  an edgeedge with one O(3)NaNi3 trigonal pyramid. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Ni(1), and two equivalent Ni(3) atoms. In the third O site, O(3) is bonded to one Na(1), one Ni(3), and two equivalent Ni(1) atoms to form distorted ONaNi3 trigonal pyramids that share corners with three equivalent O(1)Ni6 octahedra, corners with four equivalent O(5)Na2Ni3 trigonal bipyramids, corners with two equivalent O(3)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Ni6 octahedra, and edges with two equivalent O(4)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 6-14°. In the fourth O site, O(4) is bonded to two equivalent Na(1), one Ni(1), and two equivalent Ni(2) atoms to form distorted ONa2Ni3 square pyramids that share corners with two equivalent O(1)Ni6 octahedra, corners with four equivalent O(5)Na2Ni3 trigonal bipyramids, edges with three equivalent O(1)Ni6 octahedra, edges with two equivalent O(4)Na2Ni3 square pyramids,  an edgeedge with one O(5)Na2Ni3 trigonal bipyramid, and edges with two equivalent O(3)NaNi3 trigonal pyramids. The corner-sharing octahedral tilt angles are 11°. In the fifth O site, O(5) is bonded to two equivalent Na(1), one Ni(2), and two equivalent Ni(3) atoms to form distorted ONa2Ni3 trigonal bipyramids that share  a cornercorner with one O(1)Ni6 octahedra, corners with four equivalent O(4)Na2Ni3 square pyramids, corners with four equivalent O(3)NaNi3 trigonal pyramids, edges with two equivalent O(1)Ni6 octahedra,  an edgeedge with one O(4)Na2Ni3 square pyramid, and edges with two equivalent O(5)Na2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 13°.