Rb2CuP4(HO2)8 crystallizes in the triclinic P-1 space group. Rb(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(6), one O(7), one O(8), and two equivalent O(5) atoms. Cu(1) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form CuO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. There are four inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(2) and one O(6) atom. In the second H site, H(2) is bonded in a linear geometry to one O(3) and one O(7) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(8) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Rb(1), one Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one P(1), and one H(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Rb(1), one P(1), and one H(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Cu(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Rb(1), one P(2), and one H(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one P(2), and one H(2) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Rb(1), one Cu(1), one H(3), and one H(4) atom.
Rb2CuP4(HO2)8 crystallizes in the triclinic P-1 space group. Rb(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(6), one O(7), one O(8), and two equivalent O(5) atoms. The Rb(1)-O(1) bond length is 3.15 Å. The Rb(1)-O(2) bond length is 3.00 Å. The Rb(1)-O(3) bond length is 3.17 Å. The Rb(1)-O(6) bond length is 3.27 Å. The Rb(1)-O(7) bond length is 3.09 Å. The Rb(1)-O(8) bond length is 3.04 Å. There is one shorter (3.07 Å) and one longer (3.33 Å) Rb(1)-O(5) bond length. Cu(1) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form CuO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. Both Cu(1)-O(1) bond lengths are 2.00 Å. Both Cu(1)-O(5) bond lengths are 1.98 Å. Both Cu(1)-O(8) bond lengths are 2.45 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. The P(1)-O(1) bond length is 1.52 Å. The P(1)-O(2) bond length is 1.57 Å. The P(1)-O(3) bond length is 1.52 Å. The P(1)-O(4) bond length is 1.63 Å. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. The P(2)-O(4) bond length is 1.62 Å. The P(2)-O(5) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.51 Å. The P(2)-O(7) bond length is 1.58 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(2) and one O(6) atom. The H(1)-O(2) bond length is 1.04 Å. The H(1)-O(6) bond length is 1.49 Å. In the second H site, H(2) is bonded in a linear geometry to one O(3) and one O(7) atom. The H(2)-O(3) bond length is 1.50 Å. The H(2)-O(7) bond length is 1.04 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(8) atom. The H(3)-O(8) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(8) atom. The H(4)-O(8) bond length is 0.98 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Rb(1), one Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one P(1), and one H(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Rb(1), one P(1), and one H(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Cu(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Rb(1), one P(2), and one H(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one P(2), and one H(2) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Rb(1), one Cu(1), one H(3), and one H(4) atom.