CsH6(C2O3)2 crystallizes in the triclinic P-1 space group. Cs(1) is bonded in a 8-coordinate geometry to one H(1), one H(2), one O(1), one O(2), one O(5), one O(6), and two equivalent O(3) atoms. The Cs(1)-H(1) bond length is 3.18 Å. The Cs(1)-H(2) bond length is 3.18 Å. The Cs(1)-O(1) bond length is 3.29 Å. The Cs(1)-O(2) bond length is 3.07 Å. The Cs(1)-O(5) bond length is 3.15 Å. The Cs(1)-O(6) bond length is 3.10 Å. There is one shorter (3.16 Å) and one longer (3.22 Å) Cs(1)-O(3) bond length. There are four inequivalent C sites. In the first C site, C(1) is bonded in a distorted water-like geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.48 Å. The C(1)-O(2) bond length is 1.36 Å. In the second C site, C(2) is bonded in a distorted water-like geometry to one H(5) and one O(3) atom. The C(2)-H(5) bond length is 1.11 Å. The C(2)-O(3) bond length is 1.42 Å. In the third C site, C(3) is bonded in a distorted water-like geometry to one H(6) and one O(4) atom. The C(3)-H(6) bond length is 1.10 Å. The C(3)-O(4) bond length is 1.42 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(4)-O(5) bond length is 1.24 Å. The C(4)-O(6) bond length is 1.32 Å. There are six inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Cs(1) and one O(1) atom. The H(1)-O(1) bond length is 0.98 Å. In the second H site, H(2) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one O(2), and one O(3) atom. The H(2)-O(2) bond length is 1.53 Å. The H(2)-O(3) bond length is 1.05 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(4) atom. The H(3)-O(4) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a linear geometry to one O(4) and one O(6) atom. The H(4)-O(4) bond length is 1.48 Å. The H(4)-O(6) bond length is 1.04 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(2) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(3) atom. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted water-like geometry to one Cs(1), one C(4), and one H(4) atom. In the second O site, O(1) is bonded in a distorted water-like geometry to one Cs(1), one C(1), and one H(1) atom. In the third O site, O(2) is bonded in a distorted water-like geometry to one Cs(1), one C(1), and one H(2) atom. In the fourth O site, O(3) is bonded in a water-like geometry to two equivalent Cs(1), one C(2), and one H(2) atom. In the fifth O site, O(4) is bonded in a trigonal planar geometry to one C(3), one H(3), and one H(4) atom. In the sixth O site, O(5) is bonded in a single-bond geometry to one Cs(1) and one C(4) atom. Linkers: 1 [O]C(O)([C@H](O)[C@@H](O)C(=O)O)C([O])(O)[C@@H](O)[C@H](O)[C]O ,1 [O]C(=O)[C@H](O)[C@@H](O)C([O])(O)C([O])(O)[C@@H](O)[C@H](O)C(=O)O ,1 [O]C(O)([C@H](O)[C@@H](O)C(=O)O)C([O])(O)[C@@H](O)[C@H](O)C(=O)O ,1 [O]C(O)([C@H](O)[C@@H](O)[C]O)C([O])(O)[C@@H](O)[C@H](O)C(=O)O ,1 [O]C(=O)[C@@H](O)[C@H](O)C([O])(O)C([O])(O)[C@H](O)[C@@H](O)C(=O)O. Metal clusters: 2 [Cs]. The MOF has largest included sphere 1.67 A, density 2.68 g/cm3, surface area 2716.77 m2/g, accessible volume 0.05 cm3/g