Na14Cu2O9 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), one O(3), and two equivalent O(2) atoms to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(3)O4 tetrahedra,  a cornercorner with one Cu(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with nine equivalent Na(1)O4 tetrahedra,  an edgeedge with one Na(3)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, and edges with three equivalent Na(1)O4 tetrahedra. In the second Na site, Na(2) is bonded to four equivalent O(1) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Cu(1)O4 tetrahedra, corners with four equivalent Na(1)O4 tetrahedra, corners with six equivalent Na(2)O4 tetrahedra,  an edgeedge with one Na(3)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. In the third Na site, Na(3) is bonded to one O(3) and three equivalent O(1) atoms to form NaO4 tetrahedra that share  a cornercorner with one Na(3)O4 tetrahedra, corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Cu(1)O4 tetrahedra, corners with six equivalent Na(2)O4 tetrahedra, edges with three equivalent Na(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. Cu(1) is bonded to one O(2) and three equivalent O(1) atoms to form CuO4 tetrahedra that share corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(3)O4 tetrahedra, corners with six equivalent Na(2)O4 tetrahedra, edges with three equivalent Na(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), four equivalent Na(2), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing ONa6Cu pentagonal bipyramids. In the second O site, O(2) is bonded in a 7-coordinate geometry to six equivalent Na(1) and one Cu(1) atom. In the third O site, O(3) is bonded in a body-centered cubic geometry to two equivalent Na(3) and six equivalent Na(1) atoms.
Na14Cu2O9 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), one O(3), and two equivalent O(2) atoms to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(3)O4 tetrahedra,  a cornercorner with one Cu(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with nine equivalent Na(1)O4 tetrahedra,  an edgeedge with one Na(3)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, and edges with three equivalent Na(1)O4 tetrahedra. The Na(1)-O(1) bond length is 2.31 Å. The Na(1)-O(3) bond length is 2.44 Å. There is one shorter (2.39 Å) and one longer (2.41 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded to four equivalent O(1) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Cu(1)O4 tetrahedra, corners with four equivalent Na(1)O4 tetrahedra, corners with six equivalent Na(2)O4 tetrahedra,  an edgeedge with one Na(3)O4 tetrahedra,  an edgeedge with one Cu(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. There are a spread of Na(2)-O(1) bond distances ranging from 2.33-2.41 Å. In the third Na site, Na(3) is bonded to one O(3) and three equivalent O(1) atoms to form NaO4 tetrahedra that share  a cornercorner with one Na(3)O4 tetrahedra, corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Cu(1)O4 tetrahedra, corners with six equivalent Na(2)O4 tetrahedra, edges with three equivalent Na(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. The Na(3)-O(3) bond length is 2.36 Å. All Na(3)-O(1) bond lengths are 2.35 Å. Cu(1) is bonded to one O(2) and three equivalent O(1) atoms to form CuO4 tetrahedra that share corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(3)O4 tetrahedra, corners with six equivalent Na(2)O4 tetrahedra, edges with three equivalent Na(1)O4 tetrahedra, and edges with three equivalent Na(2)O4 tetrahedra. The Cu(1)-O(2) bond length is 2.00 Å. All Cu(1)-O(1) bond lengths are 2.10 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), four equivalent Na(2), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing ONa6Cu pentagonal bipyramids. In the second O site, O(2) is bonded in a 7-coordinate geometry to six equivalent Na(1) and one Cu(1) atom. In the third O site, O(3) is bonded in a body-centered cubic geometry to two equivalent Na(3) and six equivalent Na(1) atoms.