CsC4H5(NO)4 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 8-coordinate geometry to one N(3), two equivalent N(4), one H(4), one O(1), one O(3), and two equivalent O(2) atoms. The Cs(1)-N(3) bond length is 3.57 Å. There is one shorter (3.28 Å) and one longer (3.29 Å) Cs(1)-N(4) bond length. The Cs(1)-H(4) bond length is 3.34 Å. The Cs(1)-O(1) bond length is 3.09 Å. The Cs(1)-O(3) bond length is 2.98 Å. There is one shorter (3.11 Å) and one longer (3.17 Å) Cs(1)-O(2) bond length. There are four inequivalent C sites. In the first C site, C(3) is bonded in a distorted trigonal non-coplanar geometry to one N(4), one H(2), and one H(3) atom. The C(3)-N(4) bond length is 1.48 Å. The C(3)-H(2) bond length is 1.10 Å. The C(3)-H(3) bond length is 1.10 Å. In the second C site, C(4) is bonded in a distorted trigonal non-coplanar geometry to one N(3), one H(4), and one H(5) atom. The C(4)-N(3) bond length is 1.47 Å. The C(4)-H(4) bond length is 1.10 Å. The C(4)-H(5) bond length is 1.10 Å. In the third C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one N(2) atom. The C(1)-C(2) bond length is 1.48 Å. The C(1)-N(1) bond length is 1.39 Å. The C(1)-N(2) bond length is 1.38 Å. In the fourth C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one N(3), and one N(4) atom. The C(2)-N(3) bond length is 1.38 Å. The C(2)-N(4) bond length is 1.30 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one C(1), one O(1), and one O(2) atom. The N(1)-O(1) bond length is 1.27 Å. The N(1)-O(2) bond length is 1.26 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one C(1), one O(3), and one O(4) atom. The N(2)-O(3) bond length is 1.26 Å. The N(2)-O(4) bond length is 1.28 Å. In the third N site, N(3) is bonded in a distorted trigonal non-coplanar geometry to one Cs(1), one C(2), one C(4), and one H(1) atom. The N(3)-H(1) bond length is 1.02 Å. In the fourth N site, N(4) is bonded in a water-like geometry to two equivalent Cs(1), one C(2), and one C(3) atom. There are five inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one N(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(3) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(3) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one Cs(1) and one C(4) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(4) atom. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to one Cs(1) and one N(2) atom. In the second O site, O(4) is bonded in a single-bond geometry to one N(2) atom. In the third O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one N(1) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one Cs(1) and one N(1) atom. Linkers: 4 O=[N+]([O-])[C]([C]1[N]CCN1)[N+](=O)[O-]. Metal clusters: 4 [Cs]. The MOF has largest included sphere 1.89 A, density 2.34 g/cm3, surface area 3274.02 m2/g, accessible volume 0.11 cm3/g