Rb3C6N3H4O8 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one N(2), one O(2), one O(3), one O(7), one O(8), and two equivalent O(6) atoms. The Rb(1)-N(2) bond length is 3.02 Å. The Rb(1)-O(2) bond length is 2.98 Å. The Rb(1)-O(3) bond length is 2.99 Å. The Rb(1)-O(7) bond length is 2.95 Å. The Rb(1)-O(8) bond length is 2.95 Å. There is one shorter (2.91 Å) and one longer (3.16 Å) Rb(1)-O(6) bond length. In the second Rb site, Rb(2) is bonded in a 9-coordinate geometry to one N(1), one H(2), one H(3), one O(1), one O(6), one O(7), one O(8), and two equivalent O(4) atoms. The Rb(2)-N(1) bond length is 2.99 Å. The Rb(2)-H(2) bond length is 3.05 Å. The Rb(2)-H(3) bond length is 3.17 Å. The Rb(2)-O(1) bond length is 3.03 Å. The Rb(2)-O(6) bond length is 2.98 Å. The Rb(2)-O(7) bond length is 3.22 Å. The Rb(2)-O(8) bond length is 2.94 Å. There is one shorter (2.91 Å) and one longer (3.43 Å) Rb(2)-O(4) bond length. In the third Rb site, Rb(3) is bonded in a 7-coordinate geometry to one N(3), one O(1), one O(4), one O(5), one O(7), and two equivalent O(2) atoms. The Rb(3)-N(3) bond length is 3.01 Å. The Rb(3)-O(1) bond length is 3.02 Å. The Rb(3)-O(4) bond length is 2.96 Å. The Rb(3)-O(5) bond length is 2.94 Å. The Rb(3)-O(7) bond length is 3.01 Å. There is one shorter (2.95 Å) and one longer (2.96 Å) Rb(3)-O(2) bond length. There are six inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one N(1) and one N(2) atom. The C(1)-N(1) bond length is 1.34 Å. The C(1)-N(2) bond length is 1.34 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one N(2) and one N(3) atom. The C(2)-N(2) bond length is 1.34 Å. The C(2)-N(3) bond length is 1.34 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one N(1) and one N(3) atom. The C(3)-N(1) bond length is 1.34 Å. The C(3)-N(3) bond length is 1.34 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(4)-O(1) bond length is 1.27 Å. The C(4)-O(2) bond length is 1.26 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(5)-O(3) bond length is 1.28 Å. The C(5)-O(4) bond length is 1.26 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(6)-O(5) bond length is 1.27 Å. The C(6)-O(6) bond length is 1.26 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a distorted bent 120 degrees geometry to one Rb(2), one C(1), and one C(3) atom. In the second N site, N(2) is bonded in a distorted bent 120 degrees geometry to one Rb(1), one C(1), and one C(2) atom. In the third N site, N(3) is bonded in a distorted bent 120 degrees geometry to one Rb(3), one C(2), and one C(3) atom. There are four inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(7) atom. The H(1)-O(7) bond length is 1.00 Å. In the second H site, H(2) is bonded in a single-bond geometry to one Rb(2) and one O(7) atom. The H(2)-O(7) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one Rb(2) and one O(8) atom. The H(3)-O(8) bond length is 1.00 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 0.99 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(3), and one C(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(3), and one C(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to one Rb(1) and one C(5) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(3), two equivalent Rb(2), and one C(5) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Rb(3) and one C(6) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Rb(2), two equivalent Rb(1), and one C(6) atom. In the seventh O site, O(7) is bonded in a water-like geometry to one Rb(1), one Rb(2), one Rb(3), one H(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one Rb(1), one Rb(2), one H(3), and one H(4) atom. Linkers: 4 [O]C(=O)C1=NC(=[N]=C([N]1)C(=O)[O])C(=O)[O]. Metal clusters: 12 [Rb]. The MOF has largest included sphere 1.46 A, density 2.57 g/cm3, surface area 2541.25 m2/g, accessible volume 0.04 cm3/g