KNiC15H9(NO3)3(CH)3 crystallizes in the trigonal R3c space group. The structure consists of eighteen 02329_fluka molecules inside a KNiC15H9(NO3)3 framework. In the KNiC15H9(NO3)3 framework, K(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(3) atoms. All K(1)-O(1) bond lengths are 2.75 Å. All K(1)-O(3) bond lengths are 2.57 Å. Ni(1) is bonded in an octahedral geometry to three equivalent O(1) and three equivalent O(2) atoms. All Ni(1)-O(1) bond lengths are 2.05 Å. All Ni(1)-O(2) bond lengths are 2.01 Å. There are five inequivalent C sites. In the first C site, C(3) is bonded in a distorted single-bond geometry to one C(2) and one H(2) atom. The C(3)-C(2) bond length is 1.39 Å. The C(3)-H(2) bond length is 1.09 Å. In the second C site, C(5) is bonded in a distorted bent 120 degrees geometry to one N(1) and one H(4) atom. The C(5)-N(1) bond length is 1.35 Å. The C(5)-H(4) bond length is 1.09 Å. In the third C site, C(6) is bonded in a bent 120 degrees geometry to one C(2), one O(2), and one O(3) atom. The C(6)-C(2) bond length is 1.50 Å. The C(6)-O(2) bond length is 1.28 Å. The C(6)-O(3) bond length is 1.27 Å. In the fourth C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one N(1), and one O(1) atom. The C(1)-C(2) bond length is 1.44 Å. The C(1)-N(1) bond length is 1.39 Å. The C(1)-O(1) bond length is 1.27 Å. In the fifth C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(6) atom. N(1) is bonded in a trigonal planar geometry to one C(1), one C(5), and one H(1) atom. The N(1)-H(1) bond length is 1.05 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one N(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(3) atom. In the third H site, H(4) is bonded in a single-bond geometry to one C(5) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one K(1), one Ni(1), and one C(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one C(6) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(1) and one C(6) atom. Linkers: 6 [O]C(=O)c1ccc[nH]c1=O. Metal clusters: 2 [K] ,2 [Ni]. The MOF has largest included sphere 4.86 A, density 1.47 g/cm3, surface area 3518.26 m2/g, accessible volume 0.25 cm3/g