GdC10H5O9 crystallizes in the triclinic P-1 space group. Gd(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), one O(8), one O(9), and two equivalent O(4) atoms. The Gd(1)-O(1) bond length is 2.54 Å. The Gd(1)-O(2) bond length is 2.47 Å. The Gd(1)-O(3) bond length is 2.44 Å. The Gd(1)-O(5) bond length is 2.48 Å. The Gd(1)-O(6) bond length is 2.35 Å. The Gd(1)-O(8) bond length is 2.36 Å. The Gd(1)-O(9) bond length is 2.35 Å. There is one shorter (2.49 Å) and one longer (2.54 Å) Gd(1)-O(4) bond length. There are ten inequivalent C sites. In the first C site, C(1) is bonded in a distorted single-bond geometry to one C(4), one C(9), and one H(3) atom. The C(1)-C(4) bond length is 1.41 Å. The C(1)-C(9) bond length is 1.40 Å. The C(1)-H(3) bond length is 1.09 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(5), one O(3), and one O(4) atom. The C(2)-C(5) bond length is 1.49 Å. The C(2)-O(3) bond length is 1.26 Å. The C(2)-O(4) bond length is 1.28 Å. In the third C site, C(3) is bonded in a bent 120 degrees geometry to one C(8), one O(1), and one O(2) atom. The C(3)-C(8) bond length is 1.49 Å. The C(3)-O(1) bond length is 1.27 Å. The C(3)-O(2) bond length is 1.28 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one C(1), one C(10), and one C(9) atom. The C(4)-C(10) bond length is 1.48 Å. The C(4)-C(9) bond length is 1.41 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(2), one C(7), and one C(8) atom. The C(5)-C(7) bond length is 1.39 Å. The C(5)-C(8) bond length is 1.40 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one C(9), one O(6), and one O(8) atom. The C(6)-C(9) bond length is 1.52 Å. The C(6)-O(6) bond length is 1.26 Å. The C(6)-O(8) bond length is 1.27 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(5), one C(8), and one H(4) atom. The C(7)-C(8) bond length is 1.40 Å. The C(7)-H(4) bond length is 1.09 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(3), one C(5), and one C(7) atom. In the ninth C site, C(9) is bonded in a trigonal planar geometry to one C(1), one C(4), and one C(6) atom. In the tenth C site, C(10) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(5), and one O(7) atom. The C(10)-O(5) bond length is 1.25 Å. The C(10)-O(7) bond length is 1.32 Å. There are five inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(9) atom. The H(1)-O(9) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(9) atom. The H(2)-O(9) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one C(1) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(7) atom. In the fifth H site, H(5) is bonded in a linear geometry to one O(2) and one O(7) atom. The H(5)-O(2) bond length is 1.52 Å. The H(5)-O(7) bond length is 1.02 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Gd(1) and one C(3) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Gd(1), one C(3), and one H(5) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Gd(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Gd(1) and one C(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Gd(1) and one C(10) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Gd(1) and one C(6) atom. In the seventh O site, O(7) is bonded in a water-like geometry to one C(10) and one H(5) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Gd(1) and one C(6) atom. In the ninth O site, O(9) is bonded in a distorted water-like geometry to one Gd(1), one H(1), and one H(2) atom. Linkers: 1 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O ,1 [O]C(=O)c1cc(C(=O)O)c(C([O])=O)cc1C(=O)O. Metal clusters: 2 [Gd]. The MOF has largest included sphere 2.03 A, density 2.72 g/cm3, surface area 2238.12 m2/g, accessible volume 0.06 cm3/g