RbC7H4O2 crystallizes in the monoclinic P2_1/c space group. Rb(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. There is one shorter (2.85 Å) and two longer (2.92 Å) Rb(1)-O(1) bond lengths. There are a spread of Rb(1)-O(2) bond distances ranging from 2.83-3.15 Å. There are seven inequivalent C sites. In the first C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one C(5), and one H(2) atom. The C(4)-C(3) bond length is 1.39 Å. The C(4)-C(5) bond length is 1.41 Å. The C(4)-H(2) bond length is 1.09 Å. In the second C site, C(5) is bonded in a trigonal planar geometry to one C(4), one C(5), and one C(6) atom. The C(5)-C(5) bond length is 1.49 Å. The C(5)-C(6) bond length is 1.41 Å. In the third C site, C(6) is bonded in a distorted trigonal planar geometry to one C(5), one C(7), and one H(3) atom. The C(6)-C(7) bond length is 1.39 Å. The C(6)-H(3) bond length is 1.09 Å. In the fourth C site, C(7) is bonded in a distorted trigonal planar geometry to one C(2), one C(6), and one H(4) atom. The C(7)-C(2) bond length is 1.40 Å. The C(7)-H(4) bond length is 1.09 Å. In the fifth C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.51 Å. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(2) bond length is 1.27 Å. In the sixth C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(7) atom. The C(2)-C(3) bond length is 1.40 Å. In the seventh C site, C(3) is bonded in a distorted trigonal planar geometry to one C(2), one C(4), and one H(1) atom. The C(3)-H(1) bond length is 1.09 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(4) 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 single-bond geometry to one C(7) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Rb(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to three equivalent Rb(1) and one C(1) atom. Linkers: 2 [O]C(=O)c1ccc(-c2ccc(C([O])=O)cc2)cc1. Metal clusters: 4 [Rb]. The MOF has largest included sphere 2.36 A, density 1.94 g/cm3, surface area 3547.59 m2/g, accessible volume 0.10 cm3/g