KTbC7H3O9 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 9-coordinate geometry to one H(2), one O(1), one O(3), one O(6), one O(7), one O(8), one O(9), and two equivalent O(2) atoms. The K(1)-H(2) bond length is 2.96 Å. The K(1)-O(1) bond length is 3.10 Å. The K(1)-O(3) bond length is 3.08 Å. The K(1)-O(6) bond length is 2.91 Å. The K(1)-O(7) bond length is 2.72 Å. The K(1)-O(8) bond length is 2.86 Å. The K(1)-O(9) bond length is 2.94 Å. There is one shorter (3.04 Å) and one longer (3.05 Å) K(1)-O(2) bond length. Tb(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Tb(1)-O(2) bond length is 2.37 Å. The Tb(1)-O(3) bond length is 2.40 Å. The Tb(1)-O(4) bond length is 2.35 Å. The Tb(1)-O(5) bond length is 2.42 Å. The Tb(1)-O(6) bond length is 2.43 Å. The Tb(1)-O(7) bond length is 2.35 Å. The Tb(1)-O(8) bond length is 2.39 Å. The Tb(1)-O(9) bond length is 2.35 Å. 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(3), and one C(4) atom. The C(1)-C(2) bond length is 1.41 Å. The C(1)-C(3) bond length is 1.40 Å. The C(1)-C(4) bond length is 1.51 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(5) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-C(5) bond length is 1.51 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(1), one C(2), and one H(1) atom. The C(3)-H(1) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(1), and one O(2) atom. The C(4)-O(1) bond length is 1.26 Å. The C(4)-O(2) bond length is 1.28 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(3), and one O(4) atom. The C(5)-O(3) bond length is 1.27 Å. The C(5)-O(4) bond length is 1.27 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(6)-O(5) bond length is 1.28 Å. The C(6)-O(6) bond length is 1.26 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one O(7) and one O(8) atom. The C(7)-O(7) bond length is 1.27 Å. The C(7)-O(8) bond length is 1.26 Å. There are three 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 distorted single-bond geometry to one K(1), one O(1), and one O(9) atom. The H(2)-O(1) bond length is 1.65 Å. The H(2)-O(9) bond length is 1.01 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(9) atom. The H(3)-O(9) bond length is 0.99 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one K(1), one C(4), and one H(2) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent K(1), one Tb(1), and one C(4) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(1), one Tb(1), and one C(5) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Tb(1) and one C(5) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Tb(1) and one C(6) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(1), one Tb(1), and one C(6) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Tb(1), and one C(7) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(1), one Tb(1), and one C(7) atom. In the ninth O site, O(9) is bonded in a distorted water-like geometry to one K(1), one Tb(1), one H(2), and one H(3) atom. Linkers: 1 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O ,1 [O]C(=O)C([O])=O. Metal clusters: 2 [K] ,2 [Tb]. The MOF has largest included sphere 1.79 A, density 2.86 g/cm3, surface area 1348.08 m2/g, accessible volume 0.02 cm3/g