CsC7H4SO6 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 8-coordinate geometry to one O(1), one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. The Cs(1)-O(1) bond length is 3.15 Å. The Cs(1)-O(6) bond length is 3.17 Å. There is one shorter (3.00 Å) and one longer (3.18 Å) Cs(1)-O(2) bond length. There is one shorter (3.46 Å) and one longer (3.50 Å) Cs(1)-O(3) bond length. There is one shorter (3.19 Å) and one longer (3.28 Å) Cs(1)-O(5) bond length. There are seven inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(2), one C(6), and one S(1) atom. The C(1)-C(2) bond length is 1.41 Å. The C(1)-C(6) bond length is 1.41 Å. The C(1)-S(1) bond length is 1.78 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one C(1), one C(3), and one H(1) atom. The C(2)-C(3) bond length is 1.38 Å. The C(2)-H(1) bond length is 1.09 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(2), one C(4), and one C(7) atom. The C(3)-C(4) bond length is 1.46 Å. The C(3)-C(7) bond length is 1.49 Å. In the fourth C site, C(4) is bonded in a distorted single-bond geometry to one C(3) and one O(6) atom. The C(4)-O(6) bond length is 1.27 Å. In the fifth C site, C(5) is bonded in a distorted single-bond geometry to one C(6) and one H(2) atom. The C(5)-C(6) bond length is 1.37 Å. The C(5)-H(2) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted trigonal planar geometry to one C(1), one C(5), and one H(3) atom. The C(6)-H(3) bond length is 1.09 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(4), and one O(5) atom. The C(7)-O(4) bond length is 1.23 Å. The C(7)-O(5) bond length is 1.35 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(5) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(6) atom. In the fourth H site, H(4) is bonded in a bent 150 degrees geometry to one O(5) and one O(6) atom. The H(4)-O(5) bond length is 1.03 Å. The H(4)-O(6) bond length is 1.55 Å. S(1) is bonded in a distorted trigonal non-coplanar geometry to one C(1), one O(1), one O(2), and one O(3) atom. The S(1)-O(1) bond length is 1.47 Å. The S(1)-O(2) bond length is 1.47 Å. The S(1)-O(3) bond length is 1.47 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cs(1) and one S(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one S(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to two equivalent Cs(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one C(7) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to two equivalent Cs(1), one C(7), and one H(4) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Cs(1), one C(4), and one H(4) atom. Linkers: 4 [O]S([O])([O])[C]1C=CC(=O)C(C(=O)O)=C1. Metal clusters: 4 [Cs]. The MOF has largest included sphere 2.15 A, density 2.28 g/cm3, surface area 3276.70 m2/g, accessible volume 0.09 cm3/g