Rb2Cu2OI4 crystallizes in the orthorhombic P2_12_12_1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a distorted single-bond geometry to one O(1), one I(2), one I(3), two equivalent I(1), and three equivalent I(4) atoms. In the second Rb site, Rb(2) is bonded in a distorted single-bond geometry to one O(1), one I(1), one I(4), two equivalent I(2), and two equivalent I(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one I(1), one I(2), one I(3), and one I(4) atom to form edge-sharing CuI4 tetrahedra. In the second Cu site, Cu(2) is bonded to one I(1), one I(2), one I(3), and one I(4) atom to form edge-sharing CuI4 tetrahedra. O(1) is bonded in a bent 120 degrees geometry to one Rb(1) and one Rb(2) atom. There are four inequivalent I sites. In the first I site, I(1) is bonded in a 5-coordinate geometry to one Rb(2), two equivalent Rb(1), one Cu(1), and one Cu(2) atom. In the second I site, I(2) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent Rb(2), one Cu(1), and one Cu(2) atom. In the third I site, I(3) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent Rb(2), one Cu(1), and one Cu(2) atom. In the fourth I site, I(4) is bonded in a 6-coordinate geometry to one Rb(2), three equivalent Rb(1), one Cu(1), and one Cu(2) atom.
Rb2Cu2OI4 crystallizes in the orthorhombic P2_12_12_1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a distorted single-bond geometry to one O(1), one I(2), one I(3), two equivalent I(1), and three equivalent I(4) atoms. The Rb(1)-O(1) bond length is 2.77 Å. The Rb(1)-I(2) bond length is 3.79 Å. The Rb(1)-I(3) bond length is 3.70 Å. There is one shorter (3.71 Å) and one longer (3.73 Å) Rb(1)-I(1) bond length. There are a spread of Rb(1)-I(4) bond distances ranging from 3.71-3.96 Å. In the second Rb site, Rb(2) is bonded in a distorted single-bond geometry to one O(1), one I(1), one I(4), two equivalent I(2), and two equivalent I(3) atoms. The Rb(2)-O(1) bond length is 2.78 Å. The Rb(2)-I(1) bond length is 3.76 Å. The Rb(2)-I(4) bond length is 3.66 Å. There is one shorter (3.71 Å) and one longer (3.87 Å) Rb(2)-I(2) bond length. There is one shorter (3.72 Å) and one longer (3.76 Å) Rb(2)-I(3) bond length. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one I(1), one I(2), one I(3), and one I(4) atom to form edge-sharing CuI4 tetrahedra. The Cu(1)-I(1) bond length is 2.61 Å. The Cu(1)-I(2) bond length is 2.60 Å. The Cu(1)-I(3) bond length is 2.62 Å. The Cu(1)-I(4) bond length is 2.67 Å. In the second Cu site, Cu(2) is bonded to one I(1), one I(2), one I(3), and one I(4) atom to form edge-sharing CuI4 tetrahedra. The Cu(2)-I(1) bond length is 2.63 Å. The Cu(2)-I(2) bond length is 2.67 Å. The Cu(2)-I(3) bond length is 2.64 Å. The Cu(2)-I(4) bond length is 2.61 Å. O(1) is bonded in a bent 120 degrees geometry to one Rb(1) and one Rb(2) atom. There are four inequivalent I sites. In the first I site, I(1) is bonded in a 5-coordinate geometry to one Rb(2), two equivalent Rb(1), one Cu(1), and one Cu(2) atom. In the second I site, I(2) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent Rb(2), one Cu(1), and one Cu(2) atom. In the third I site, I(3) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent Rb(2), one Cu(1), and one Cu(2) atom. In the fourth I site, I(4) is bonded in a 6-coordinate geometry to one Rb(2), three equivalent Rb(1), one Cu(1), and one Cu(2) atom.