Rb2Cr4Cu(HO4)4 crystallizes in the triclinic P-1 space group. Rb(1) is bonded in a 11-coordinate geometry to one H(1), one O(1), one O(2), one O(4), one O(7), two equivalent O(5), two equivalent O(6), and two equivalent O(8) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form CrO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one Cr(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. Cu(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(7) atoms to form distorted CuO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra and corners with two equivalent Cr(2)O4 tetrahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Rb(1) and one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(3) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Rb(1), one Cr(1), and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(1), one Cr(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Cu(1), one H(1), and one H(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1) and one Cr(1) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to two equivalent Rb(1) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Rb(1) and one Cr(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Rb(1), one Cr(1), and one Cu(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Rb(1) and one Cr(1) atom.
Rb2Cr4Cu(HO4)4 crystallizes in the triclinic P-1 space group. Rb(1) is bonded in a 11-coordinate geometry to one H(1), one O(1), one O(2), one O(4), one O(7), two equivalent O(5), two equivalent O(6), and two equivalent O(8) atoms. The Rb(1)-H(1) bond length is 3.06 Å. The Rb(1)-O(1) bond length is 3.41 Å. The Rb(1)-O(2) bond length is 3.26 Å. The Rb(1)-O(4) bond length is 2.91 Å. The Rb(1)-O(7) bond length is 3.23 Å. There is one shorter (2.95 Å) and one longer (3.22 Å) Rb(1)-O(5) bond length. There is one shorter (3.08 Å) and one longer (3.23 Å) Rb(1)-O(6) bond length. There is one shorter (2.91 Å) and one longer (3.08 Å) Rb(1)-O(8) bond length. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form CrO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one Cr(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. The Cr(1)-O(1) bond length is 1.80 Å. The Cr(1)-O(4) bond length is 1.62 Å. The Cr(1)-O(7) bond length is 1.67 Å. The Cr(1)-O(8) bond length is 1.62 Å. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. The Cr(2)-O(1) bond length is 1.79 Å. The Cr(2)-O(2) bond length is 1.64 Å. The Cr(2)-O(5) bond length is 1.62 Å. The Cr(2)-O(6) bond length is 1.66 Å. Cu(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(7) atoms to form distorted CuO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra and corners with two equivalent Cr(2)O4 tetrahedra. Both Cu(1)-O(2) bond lengths are 2.42 Å. Both Cu(1)-O(3) bond lengths are 2.02 Å. Both Cu(1)-O(7) bond lengths are 1.92 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Rb(1) and one O(3) atom. The H(1)-O(3) bond length is 0.97 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(3) atom. The H(2)-O(3) bond length is 1.01 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Rb(1), one Cr(1), and one Cr(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(1), one Cr(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Cu(1), one H(1), and one H(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1) and one Cr(1) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to two equivalent Rb(1) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Rb(1) and one Cr(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Rb(1), one Cr(1), and one Cu(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Rb(1) and one Cr(1) atom.