Rb4CO4 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 4-coordinate geometry to four equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) 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 single-bond geometry to four equivalent Rb(2) and one C(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to two equivalent Rb(2), four equivalent Rb(1), and one C(1) atom.
Rb4CO4 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 4-coordinate geometry to four equivalent O(2) atoms. All Rb(1)-O(2) bond lengths are 2.97 Å. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Both Rb(2)-O(2) bond lengths are 3.32 Å. There are two shorter (3.15 Å) and two longer (3.31 Å) Rb(2)-O(1) bond lengths. 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 1.47 Å. Both C(1)-O(2) bond lengths are 1.42 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to four equivalent Rb(2) and one C(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to two equivalent Rb(2), four equivalent Rb(1), and one C(1) atom.