TmH4(C3O4)2 crystallizes in the monoclinic P2_1/c space group. Tm(1) is bonded in a 8-coordinate geometry to one O(1), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(2) atoms. The Tm(1)-O(1) bond length is 2.32 Å. The Tm(1)-O(4) bond length is 2.27 Å. The Tm(1)-O(5) bond length is 2.27 Å. The Tm(1)-O(6) bond length is 2.27 Å. The Tm(1)-O(7) bond length is 2.30 Å. The Tm(1)-O(8) bond length is 2.25 Å. There is one shorter (2.48 Å) and one longer (2.60 Å) Tm(1)-O(2) bond length. There are six 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 trigonal planar geometry to one C(1), one C(2), and one C(6) atom. The C(3)-C(6) bond length is 1.51 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(3), and one O(4) atom. The C(4)-O(3) bond length is 1.27 Å. The C(4)-O(4) 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(5), and one O(6) atom. The C(5)-O(5) bond length is 1.26 Å. The C(5)-O(6) bond length is 1.28 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(7), and one O(8) atom. The C(6)-O(7) bond length is 1.28 Å. The C(6)-O(8) bond length is 1.26 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(1) and one O(3) atom. The H(1)-O(1) bond length is 1.00 Å. The H(1)-O(3) bond length is 1.67 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(1) atom. The H(2)-O(1) bond length is 0.98 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(2) and one O(3) atom. The H(3)-O(2) bond length is 1.01 Å. The H(3)-O(3) bond length is 1.68 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(2) atom. The H(4)-O(2) bond length is 0.99 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Tm(1), one H(1), and one H(2) atom. In the second O site, O(2) is bonded in a water-like geometry to two equivalent Tm(1), one H(3), and one H(4) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one C(4), one H(1), and one H(3) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Tm(1) and one C(4) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Tm(1) and one C(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Tm(1) and one C(5) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Tm(1) and one C(6) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Tm(1) and one C(6) atom. Linkers: 4 [O]C(=O)c1c([C]=O)c(C([O])=O)c(C([O])=O)c(C([O])=O)c1C([O])=O ,2 [O]C(=O)c1c(C([O])=O)c(C([O])=O)c(C([O])=O)c(C([O])=O)c1C([O])=O. Metal clusters: 4 [Tm]. The MOF has largest included sphere 2.31 A, density 3.26 g/cm3, surface area 1666.73 m2/g, accessible volume 0.05 cm3/g