Rb4CO4 crystallizes in the monoclinic C2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 5-coordinate geometry to two equivalent O(1) and three equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. C(1) is bonded in a tetrahedral geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two 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), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Rb(2), three equivalent Rb(1), and one C(1) atom.
Rb4CO4 crystallizes in the monoclinic C2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 5-coordinate geometry to two equivalent O(1) and three equivalent O(2) atoms. There is one shorter (2.62 Å) and one longer (2.94 Å) Rb(1)-O(1) bond length. There are a spread of Rb(1)-O(2) bond distances ranging from 2.72-3.34 Å. In the second Rb site, Rb(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.69 Å) and one longer (2.73 Å) Rb(2)-O(1) bond length. There is one shorter (2.88 Å) and one longer (3.06 Å) Rb(2)-O(2) bond length. C(1) is bonded in a tetrahedral geometry to two equivalent O(1) and two equivalent O(2) atoms. Both C(1)-O(1) bond lengths are 1.46 Å. Both C(1)-O(2) bond lengths are 1.43 Å. There are two 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), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Rb(2), three equivalent Rb(1), and one C(1) atom.