RbNa7(CoO3)2 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a distorted square co-planar geometry to four equivalent O(3) atoms. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1) and three equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing NaO4 tetrahedra. In the third Na site, Na(3) is bonded to one O(1) and three equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing NaO4 tetrahedra. In the fourth Na site, Na(4) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Co(1) is bonded in a distorted trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), two equivalent Na(1), and one Co(1) atom. In the second O site, O(2) is bonded to one Na(1), one Na(4), three equivalent Na(3), and one Co(1) atom to form a mixture of corner and edge-sharing ONa5Co octahedra. The corner-sharing octahedral tilt angles range from 0-31°. In the third O site, O(3) is bonded in a 5-coordinate geometry to two equivalent Rb(1), one Na(1), three equivalent Na(2), and one Co(1) atom.
RbNa7(CoO3)2 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a distorted square co-planar geometry to four equivalent O(3) atoms. All Rb(1)-O(3) bond lengths are 3.20 Å. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Na(1)-O(2) bond length is 2.33 Å. The Na(1)-O(3) bond length is 2.60 Å. Both Na(1)-O(1) bond lengths are 2.32 Å. In the second Na site, Na(2) is bonded to one O(1) and three equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing NaO4 tetrahedra. The Na(2)-O(1) bond length is 2.34 Å. There is one shorter (2.34 Å) and two longer (2.41 Å) Na(2)-O(3) bond lengths. In the third Na site, Na(3) is bonded to one O(1) and three equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing NaO4 tetrahedra. The Na(3)-O(1) bond length is 2.52 Å. There are two shorter (2.30 Å) and one longer (2.35 Å) Na(3)-O(2) bond length. In the fourth Na site, Na(4) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Na(4)-O(1) bond lengths are 2.63 Å. Both Na(4)-O(2) bond lengths are 2.26 Å. Co(1) is bonded in a distorted trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Co(1)-O(1) bond length is 1.85 Å. The Co(1)-O(2) bond length is 1.93 Å. The Co(1)-O(3) bond length is 1.84 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), two equivalent Na(1), and one Co(1) atom. In the second O site, O(2) is bonded to one Na(1), one Na(4), three equivalent Na(3), and one Co(1) atom to form a mixture of corner and edge-sharing ONa5Co octahedra. The corner-sharing octahedral tilt angles range from 0-31°. In the third O site, O(3) is bonded in a 5-coordinate geometry to two equivalent Rb(1), one Na(1), three equivalent Na(2), and one Co(1) atom.