KCo(HCOO)3 crystallizes in the monoclinic C2 space group. K(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The K(1)-O(1) bond length is 2.83 Å. The K(1)-O(2) bond length is 2.83 Å. The K(1)-O(3) bond length is 2.83 Å. The K(1)-O(4) bond length is 2.83 Å. The K(1)-O(5) bond length is 2.83 Å. The K(1)-O(6) bond length is 2.83 Å. Co(1) is bonded in an octahedral geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Co(1)-O(1) bond length is 2.11 Å. The Co(1)-O(2) bond length is 2.11 Å. The Co(1)-O(3) bond length is 2.11 Å. The Co(1)-O(4) bond length is 2.11 Å. The Co(1)-O(5) bond length is 2.11 Å. The Co(1)-O(6) bond length is 2.11 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one H(1,2,3,4); one O(1); and one O(3) atom. The C(1)-H(1,2,3,4) bond length is 1.10 Å. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(3) bond length is 1.27 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one H(1,2,3,4) and two equivalent O(2) atoms. The C(2)-H(1,2,3,4) bond length is 1.10 Å. Both C(2)-O(2) bond lengths are 1.27 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one H(1,2,3,4); one O(4); and one O(6) atom. The C(3)-H(1,2,3,4) bond length is 1.10 Å. The C(3)-O(4) bond length is 1.27 Å. The C(3)-O(6) bond length is 1.27 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one H(1,2,3,4) and two equivalent O(5) atoms. The C(4)-H(1,2,3,4) bond length is 1.10 Å. Both C(4)-O(5) bond lengths are 1.27 Å. H(1,2,3,4) is bonded in a single-bond geometry to one C(1) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one C(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one C(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one C(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one C(3) atom. Linkers: 6 [O]C=O. Metal clusters: 2 [K] ,2 [Co]. The MOF has largest included sphere 2.55 A, density 2.13 g/cm3, surface area 0.00 m2/g, accessible volume 0.00 cm3/g