TbH(CO2)3 crystallizes in the orthorhombic Pnma space group. Tb(1) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. The Tb(1)-O(2) bond length is 2.42 Å. There is one shorter (2.43 Å) and one longer (2.47 Å) Tb(1)-O(1) bond length. Both Tb(1)-O(3) bond lengths are 2.40 Å. There are two shorter (2.44 Å) and two longer (2.47 Å) Tb(1)-O(4) bond lengths. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one H(1), one O(1), and one O(2) atom. The C(1)-H(1) bond length is 1.10 Å. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(2) bond length is 1.26 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(2)-O(3) bond length is 1.25 Å. The C(2)-O(4) bond length is 1.28 Å. H(1) is bonded in a single-bond geometry to one C(1) atom. There are four inequivalent O sites. In the first O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Tb(1) and one C(2) atom. In the second O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Tb(1) and one C(1) atom. In the third O site, O(2) is bonded in a distorted single-bond geometry to one Tb(1) and one C(1) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Tb(1) and one C(2) atom. Linkers: 4 [O]C(=O)C([O])=O. Metal clusters: 4 [Tb]. The MOF has largest included sphere 1.27 A, density 3.92 g/cm3, surface area 1216.23 m2/g, accessible volume 0.02 cm3/g