KC4N7H6O5 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 7-coordinate geometry to one N(1), one N(2), one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The K(1)-N(1) bond length is 2.92 Å. The K(1)-N(2) bond length is 3.12 Å. The K(1)-O(1) bond length is 2.91 Å. The K(1)-O(2) bond length is 2.99 Å. The K(1)-O(3) bond length is 2.69 Å. The K(1)-O(4) bond length is 2.63 Å. The K(1)-O(5) bond length is 2.81 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(4) atom. The C(1)-N(1) bond length is 1.35 Å. The C(1)-N(2) bond length is 1.38 Å. The C(1)-N(4) bond length is 1.33 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(1), one N(3), and one N(5) atom. The C(2)-N(1) bond length is 1.35 Å. The C(2)-N(3) bond length is 1.37 Å. The C(2)-N(5) bond length is 1.34 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(4), one N(2), and one N(3) atom. The C(3)-C(4) bond length is 1.49 Å. The C(3)-N(2) bond length is 1.33 Å. The C(3)-N(3) bond length is 1.34 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one N(6), and one N(7) atom. The C(4)-N(6) bond length is 1.38 Å. The C(4)-N(7) bond length is 1.38 Å. There are seven inequivalent N sites. In the first N site, N(1) is bonded in a distorted bent 120 degrees geometry to one K(1), one C(1), and one C(2) atom. In the second N site, N(2) is bonded in a distorted bent 120 degrees geometry to one K(1), one C(1), and one C(3) atom. In the third N site, N(3) is bonded in a distorted bent 120 degrees geometry to one C(2) and one C(3) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one C(1), one H(5), and one H(6) atom. The N(4)-H(5) bond length is 1.02 Å. The N(4)-H(6) bond length is 1.03 Å. In the fifth N site, N(5) is bonded in a trigonal planar geometry to one C(2), one H(3), and one H(4) atom. The N(5)-H(3) bond length is 1.02 Å. The N(5)-H(4) bond length is 1.01 Å. In the sixth N site, N(6) is bonded in a trigonal planar geometry to one C(4), one O(2), and one O(5) atom. The N(6)-O(2) bond length is 1.25 Å. The N(6)-O(5) bond length is 1.28 Å. In the seventh N site, N(7) is bonded in a trigonal planar geometry to one C(4), one O(3), and one O(4) atom. The N(7)-O(3) bond length is 1.28 Å. The N(7)-O(4) bond length is 1.25 Å. There are six inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. The H(1)-O(1) bond length is 1.00 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 N(5) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one N(5) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one N(4) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one N(4) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one K(1), one H(1), and one H(2) atom. In the second O site, O(2) is bonded in a single-bond geometry to one K(1) and one N(6) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one K(1) and one N(7) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one K(1) and one N(7) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one K(1) and one N(6) atom. Linkers: 1 NC1=[N]=C(N)N=C([N]1)[C](N(=O)=O)N(=O)=O ,3 NC1=NC(=[N]=C([N]1)N)[C](N(=O)=O)N(=O)=O. Metal clusters: 4 [K]. The MOF has largest included sphere 1.36 A, density 1.88 g/cm3, surface area 2372.65 m2/g, accessible volume 0.03 cm3/g