TbH4(CO2)4 crystallizes in the orthorhombic C222_1 space group. Tb(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both Tb(1)-O(1) bond lengths are 2.36 Å. Both Tb(1)-O(2) bond lengths are 2.42 Å. Both Tb(1)-O(3) bond lengths are 2.31 Å. Both Tb(1)-O(4) bond lengths are 2.43 Å. There are three 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 0.93 Å. The C(1)-O(1) bond length is 1.24 Å. The C(1)-O(2) bond length is 1.24 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one H(2) and two equivalent O(3) atoms. The C(2)-H(2) bond length is 0.93 Å. Both C(2)-O(3) bond lengths are 1.24 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one H(3) and two equivalent O(4) atoms. The C(3)-H(3) bond length is 0.93 Å. Both C(3)-O(4) bond lengths are 1.25 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(3) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Tb(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Tb(1) and one C(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Tb(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Tb(1) and one C(3) atom. Linkers: 14 [O]C=O. Metal clusters: 4 [Tb]. The MOF has largest included sphere 4.00 A, density 2.14 g/cm3, surface area 2686.79 m2/g, accessible volume 0.19 cm3/g