KGdC10H2O9 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(5), one O(7), one O(8), one O(9), and two equivalent O(6) atoms. The K(1)-O(2) bond length is 2.79 Å. The K(1)-O(3) bond length is 2.73 Å. The K(1)-O(5) bond length is 3.08 Å. The K(1)-O(7) bond length is 2.96 Å. The K(1)-O(8) bond length is 3.06 Å. The K(1)-O(9) bond length is 2.97 Å. There is one shorter (2.64 Å) and one longer (2.78 Å) K(1)-O(6) bond length. Gd(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(7), one O(8), and one O(9) atom. The Gd(1)-O(1) bond length is 2.49 Å. The Gd(1)-O(2) bond length is 2.45 Å. The Gd(1)-O(3) bond length is 2.58 Å. The Gd(1)-O(4) bond length is 2.42 Å. The Gd(1)-O(5) bond length is 2.31 Å. The Gd(1)-O(7) bond length is 2.59 Å. The Gd(1)-O(8) bond length is 2.45 Å. The Gd(1)-O(9) bond length is 2.44 Å. There are ten inequivalent C sites. In the first C site, C(1) is bonded in a distorted single-bond geometry to one C(2), one C(3), and one H(1) atom. The C(1)-C(2) bond length is 1.38 Å. The C(1)-C(3) bond length is 1.39 Å. The C(1)-H(1) bond length is 0.93 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(4) atom. The C(2)-C(3) bond length is 1.39 Å. The C(2)-C(4) 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(5) atom. The C(3)-C(5) bond length is 1.50 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(4)-O(1) bond length is 1.25 Å. The C(4)-O(2) bond length is 1.26 Å. In the fifth C site, C(5) is bonded in a bent 120 degrees geometry to one C(3), one O(3), and one O(4) atom. The C(5)-O(3) bond length is 1.25 Å. The C(5)-O(4) bond length is 1.26 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(10), one C(8), and one C(9) atom. The C(6)-C(10) bond length is 1.49 Å. The C(6)-C(8) bond length is 1.41 Å. The C(6)-C(9) bond length is 1.39 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(8), one O(5), and one O(6) atom. The C(7)-C(8) bond length is 1.51 Å. The C(7)-O(5) bond length is 1.27 Å. The C(7)-O(6) bond length is 1.23 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(6), one C(7), and one C(9) atom. The C(8)-C(9) bond length is 1.39 Å. In the ninth C site, C(9) is bonded in a distorted single-bond geometry to one C(6), one C(8), and one H(2) atom. The C(9)-H(2) bond length is 0.93 Å. In the tenth C site, C(10) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(7), and one O(8) atom. The C(10)-O(7) bond length is 1.26 Å. The C(10)-O(8) bond length is 1.27 Å. There are two 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(9) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one Gd(1) and one C(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), one Gd(1), and one C(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Gd(1), and one C(5) atom. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Gd(1) and one C(5) atom. In the fifth O site, O(5) is bonded in a 1-coordinate geometry to one K(1), one Gd(1), and one C(7) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to two equivalent K(1) and one C(7) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one K(1), one Gd(1), and one C(10) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(1), one Gd(1), and one C(10) atom. In the ninth O site, O(9) is bonded in an L-shaped geometry to one K(1) and one Gd(1) atom. Linkers: 2 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 2 [K] ,2 [Gd]. The MOF has largest included sphere 5.06 A, density 1.67 g/cm3, surface area 2297.44 m2/g, accessible volume 0.28 cm3/g