RbC5N3H2O5 crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 9-coordinate geometry to two equivalent N(1), one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There is one shorter (3.18 Å) and one longer (3.27 Å) Rb(1)-N(1) bond length. The Rb(1)-O(5) bond length is 3.05 Å. There is one shorter (2.96 Å) and one longer (3.07 Å) Rb(1)-O(1) bond length. There is one shorter (3.09 Å) and one longer (3.31 Å) Rb(1)-O(2) bond length. There is one shorter (2.87 Å) and one longer (2.88 Å) Rb(1)-O(3) bond length. There are five inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one N(1), and one H(1) atom. The C(1)-C(2) bond length is 1.39 Å. The C(1)-N(1) bond length is 1.34 Å. The C(1)-H(1) bond length is 1.09 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one C(3), and one N(2) atom. The C(2)-C(3) bond length is 1.46 Å. The C(2)-N(2) bond length is 1.44 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(2), one C(4), and one O(3) atom. The C(3)-C(4) bond length is 1.46 Å. The C(3)-O(3) bond length is 1.25 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one C(5), and one N(3) atom. The C(4)-C(5) bond length is 1.39 Å. The C(4)-N(3) bond length is 1.44 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(4), one N(1), and one H(2) atom. The C(5)-N(1) bond length is 1.34 Å. The C(5)-H(2) bond length is 1.09 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Rb(1), one C(1), and one C(5) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one C(2), one O(1), and one O(2) atom. The N(2)-O(1) bond length is 1.25 Å. The N(2)-O(2) bond length is 1.25 Å. In the third N site, N(3) is bonded in a trigonal planar geometry to one C(4), one O(4), and one O(5) atom. The N(3)-O(4) bond length is 1.24 Å. The N(3)-O(5) bond length is 1.25 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Rb(1) and one N(2) atom. In the second O site, O(5) is bonded in a distorted single-bond geometry to one Rb(1) and one N(3) atom. In the third O site, O(2) is bonded in a single-bond geometry to two equivalent Rb(1) and one N(2) atom. In the fourth O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Rb(1) and one C(3) atom. In the fifth O site, O(4) is bonded in a single-bond geometry to one N(3) atom. Linkers: 4 O=C1[C]([N+](=O)[O-])C=NC=C1[N+](=O)[O-]. Metal clusters: 4 [Rb]. RCSR code: fes. The MOF has largest included sphere 1.48 A, density 2.19 g/cm3, surface area 3271.43 m2/g, accessible volume 0.05 cm3/g