Rb2CoO3 crystallizes in the monoclinic Cm space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. In the third Rb site, Rb(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. In the fourth Rb site, Rb(4) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(6), and two equivalent O(7) atoms. In the second Co site, Co(2) is bonded to one O(4), two equivalent O(5), and two equivalent O(7) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. In the third Co site, Co(3) is bonded to one O(1), two equivalent O(5), and two equivalent O(8) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. In the fourth Co site, Co(4) is bonded to one O(3), two equivalent O(6), and two equivalent O(8) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(3), and one Co(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(4), and one Co(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(3), two equivalent Rb(4), and one Co(4) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Rb(2), two equivalent Rb(3), two equivalent Rb(4), and one Co(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(2), and one Co(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(1), and one Co(4) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(1), and one Co(2) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(3), and one Co(4) atom.
Rb2CoO3 crystallizes in the monoclinic Cm space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom. The Rb(1)-O(1) bond length is 3.24 Å. The Rb(1)-O(2) bond length is 3.13 Å. The Rb(1)-O(3) bond length is 3.02 Å. The Rb(1)-O(5) bond length is 2.89 Å. The Rb(1)-O(6) bond length is 2.94 Å. The Rb(1)-O(7) bond length is 2.88 Å. The Rb(1)-O(8) bond length is 2.91 Å. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Rb(2)-O(1) bond length is 3.12 Å. The Rb(2)-O(2) bond length is 3.26 Å. The Rb(2)-O(4) bond length is 3.01 Å. The Rb(2)-O(5) bond length is 2.93 Å. The Rb(2)-O(6) bond length is 2.85 Å. The Rb(2)-O(7) bond length is 2.91 Å. The Rb(2)-O(8) bond length is 2.93 Å. In the third Rb site, Rb(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Rb(3)-O(1) bond length is 3.01 Å. The Rb(3)-O(3) bond length is 3.12 Å. The Rb(3)-O(4) bond length is 3.23 Å. The Rb(3)-O(5) bond length is 2.91 Å. The Rb(3)-O(6) bond length is 2.93 Å. The Rb(3)-O(7) bond length is 2.90 Å. The Rb(3)-O(8) bond length is 2.92 Å. In the fourth Rb site, Rb(4) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Rb(4)-O(2) bond length is 3.01 Å. The Rb(4)-O(3) bond length is 3.26 Å. The Rb(4)-O(4) bond length is 3.13 Å. The Rb(4)-O(5) bond length is 2.94 Å. The Rb(4)-O(6) bond length is 2.89 Å. The Rb(4)-O(7) bond length is 2.89 Å. The Rb(4)-O(8) bond length is 2.89 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(6), and two equivalent O(7) atoms. The Co(1)-O(2) bond length is 1.78 Å. Both Co(1)-O(6) bond lengths are 1.93 Å. Both Co(1)-O(7) bond lengths are 1.97 Å. In the second Co site, Co(2) is bonded to one O(4), two equivalent O(5), and two equivalent O(7) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. The Co(2)-O(4) bond length is 1.80 Å. Both Co(2)-O(5) bond lengths are 1.90 Å. Both Co(2)-O(7) bond lengths are 1.89 Å. In the third Co site, Co(3) is bonded to one O(1), two equivalent O(5), and two equivalent O(8) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. The Co(3)-O(1) bond length is 1.80 Å. Both Co(3)-O(5) bond lengths are 1.89 Å. Both Co(3)-O(8) bond lengths are 1.90 Å. In the fourth Co site, Co(4) is bonded to one O(3), two equivalent O(6), and two equivalent O(8) atoms to form distorted edge-sharing CoO5 trigonal bipyramids. The Co(4)-O(3) bond length is 1.79 Å. Both Co(4)-O(6) bond lengths are 1.90 Å. Both Co(4)-O(8) bond lengths are 1.90 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(3), and one Co(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(4), and one Co(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Rb(1), two equivalent Rb(3), two equivalent Rb(4), and one Co(4) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Rb(2), two equivalent Rb(3), two equivalent Rb(4), and one Co(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(2), and one Co(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(1), and one Co(4) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(1), and one Co(2) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Rb(1), one Rb(2), one Rb(3), one Rb(4), one Co(3), and one Co(4) atom.