CsH3(CO2)4(CH)4 crystallizes in the triclinic P-1 space group. The structure consists of eight 02329_fluka molecules inside a CsH3(CO2)4 framework. In the CsH3(CO2)4 framework, Cs(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(7), one O(8), and three equivalent O(4) atoms. The Cs(1)-O(1) bond length is 3.16 Å. The Cs(1)-O(3) bond length is 3.29 Å. The Cs(1)-O(7) bond length is 3.16 Å. The Cs(1)-O(8) bond length is 3.16 Å. There are a spread of Cs(1)-O(4) bond distances ranging from 3.16-3.30 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.29 Å. In the second C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(4)-O(3) bond length is 1.32 Å. The C(4)-O(4) bond length is 1.24 Å. In the third C site, C(5) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(5)-O(5) bond length is 1.30 Å. The C(5)-O(6) bond length is 1.26 Å. In the fourth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one O(7) and one O(8) atom. The C(8)-O(7) bond length is 1.32 Å. The C(8)-O(8) bond length is 1.24 Å. There are three inequivalent H sites. In the first H site, H(3) is bonded in a linear geometry to one O(1) and one O(3) atom. The H(3)-O(1) bond length is 1.40 Å. The H(3)-O(3) bond length is 1.07 Å. In the second H site, H(4) is bonded in a linear geometry to one O(2) and one O(5) atom. The H(4)-O(2) bond length is 1.29 Å. The H(4)-O(5) bond length is 1.16 Å. In the third H site, H(7) is bonded in a linear geometry to one O(6) and one O(7) atom. The H(7)-O(6) bond length is 1.44 Å. The H(7)-O(7) bond length is 1.05 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Cs(1), one C(1), and one H(3) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one C(1) and one H(4) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Cs(1), one C(4), and one H(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to three equivalent Cs(1) and one C(4) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one C(5) and one H(4) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one C(5) and one H(7) atom. In the seventh O site, O(7) is bonded in a distorted water-like geometry to one Cs(1), one C(8), and one H(7) atom. In the eighth O site, O(8) is bonded in a single-bond geometry to one Cs(1) and one C(8) atom. Linkers: 2 [O]C(=O)/C=C\C(=O)O. Metal clusters: 2 [Cs]. The MOF has largest included sphere 2.19 A, density 2.05 g/cm3, surface area 3748.70 m2/g, accessible volume 0.09 cm3/g