KLa(CO2)5 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(7) atom. The K(1)-O(1) bond length is 2.95 Å. The K(1)-O(2) bond length is 2.93 Å. The K(1)-O(4) bond length is 2.64 Å. The K(1)-O(7) bond length is 2.78 Å. La(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The La(1)-O(1) bond length is 2.55 Å. The La(1)-O(10) bond length is 2.58 Å. The La(1)-O(3) bond length is 2.47 Å. The La(1)-O(5) bond length is 2.54 Å. The La(1)-O(6) bond length is 2.54 Å. The La(1)-O(7) bond length is 2.56 Å. The La(1)-O(8) bond length is 2.56 Å. The La(1)-O(9) bond length is 2.59 Å. There are five inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.25 Å. The C(1)-O(2) bond length is 1.24 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 1.22 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(10) and one O(5) atom. The C(3)-O(10) bond length is 1.25 Å. The C(3)-O(5) bond length is 1.23 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(6) and one O(8) atom. The C(4)-O(6) bond length is 1.25 Å. The C(4)-O(8) bond length is 1.24 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one O(7) and one O(9) atom. The C(5)-O(7) bond length is 1.25 Å. The C(5)-O(9) bond length is 1.24 Å. There are ten inequivalent O sites. In the first O site, O(9) is bonded in a distorted bent 120 degrees geometry to one La(1) and one C(5) atom. In the second O site, O(10) is bonded in a distorted bent 120 degrees geometry to one La(1) and one C(3) atom. In the third O site, O(1) is bonded in a distorted single-bond geometry to one K(1), one La(1), and one C(1) atom. In the fourth O site, O(2) is bonded in a distorted single-bond geometry to one K(1) and one C(1) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one La(1) and one C(2) atom. In the sixth O site, O(4) is bonded in a bent 120 degrees geometry to one K(1) and one C(2) atom. In the seventh O site, O(5) is bonded in a distorted bent 120 degrees geometry to one La(1) and one C(3) atom. In the eighth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one La(1) and one C(4) atom. In the ninth O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one K(1), one La(1), and one C(5) atom. In the tenth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one La(1) and one C(4) atom. Linkers: 20 [O]C(=O)C([O])=O. Metal clusters: 8 [K] ,8 [La]. The MOF has largest included sphere 4.95 A, density 1.50 g/cm3, surface area 2852.96 m2/g, accessible volume 0.29 cm3/g