Na14Co2O9 crystallizes in the trigonal P-3 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1) and three equivalent O(3) atoms to form NaO4 tetrahedra that share  a cornercorner with one Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra, corners with three equivalent Co(1)O4 tetrahedra, corners with six equivalent Na(3)O4 tetrahedra, edges with three equivalent Na(2)O4 tetrahedra, and edges with three equivalent Na(3)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(1)O4 tetrahedra,  a cornercorner with one Co(1)O4 tetrahedra, corners with four equivalent Na(3)O4 tetrahedra, corners with nine equivalent Na(2)O4 tetrahedra,  an edgeedge with one Na(1)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. In the third Na site, Na(3) is bonded to four equivalent O(3) atoms to form NaO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Co(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with six equivalent Na(3)O4 tetrahedra,  an edgeedge with one Na(1)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and edges with three equivalent Na(3)O4 tetrahedra. Co(1) is bonded to one O(2) and three equivalent O(3) atoms to form CoO4 tetrahedra that share corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra, corners with six equivalent Na(3)O4 tetrahedra, edges with three equivalent Na(2)O4 tetrahedra, and edges with three equivalent Na(3)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a body-centered cubic geometry to two equivalent Na(1) and six equivalent Na(2) atoms. In the second O site, O(2) is bonded in a 7-coordinate geometry to six equivalent Na(2) and one Co(1) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), four equivalent Na(3), and one Co(1) atom to form a mixture of distorted corner and edge-sharing ONa6Co pentagonal bipyramids.
Na14Co2O9 crystallizes in the trigonal P-3 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1) and three equivalent O(3) atoms to form NaO4 tetrahedra that share  a cornercorner with one Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra, corners with three equivalent Co(1)O4 tetrahedra, corners with six equivalent Na(3)O4 tetrahedra, edges with three equivalent Na(2)O4 tetrahedra, and edges with three equivalent Na(3)O4 tetrahedra. The Na(1)-O(1) bond length is 2.35 Å. All Na(1)-O(3) bond lengths are 2.39 Å. In the second Na site, Na(2) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(1)O4 tetrahedra,  a cornercorner with one Co(1)O4 tetrahedra, corners with four equivalent Na(3)O4 tetrahedra, corners with nine equivalent Na(2)O4 tetrahedra,  an edgeedge with one Na(1)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. The Na(2)-O(1) bond length is 2.45 Å. The Na(2)-O(3) bond length is 2.35 Å. There is one shorter (2.38 Å) and one longer (2.42 Å) Na(2)-O(2) bond length. In the third Na site, Na(3) is bonded to four equivalent O(3) atoms to form NaO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Co(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with six equivalent Na(3)O4 tetrahedra,  an edgeedge with one Na(1)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and edges with three equivalent Na(3)O4 tetrahedra. There are a spread of Na(3)-O(3) bond distances ranging from 2.35-2.41 Å. Co(1) is bonded to one O(2) and three equivalent O(3) atoms to form CoO4 tetrahedra that share corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra, corners with six equivalent Na(3)O4 tetrahedra, edges with three equivalent Na(2)O4 tetrahedra, and edges with three equivalent Na(3)O4 tetrahedra. The Co(1)-O(2) bond length is 2.04 Å. All Co(1)-O(3) bond lengths are 2.06 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a body-centered cubic geometry to two equivalent Na(1) and six equivalent Na(2) atoms. In the second O site, O(2) is bonded in a 7-coordinate geometry to six equivalent Na(2) and one Co(1) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), four equivalent Na(3), and one Co(1) atom to form a mixture of distorted corner and edge-sharing ONa6Co pentagonal bipyramids.