CaC12H8(NO3)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Ca(1)-O(1) bond lengths are 2.36 Å. Both Ca(1)-O(2) bond lengths are 2.34 Å. Both Ca(1)-O(3) bond lengths are 2.35 Å. There are six inequivalent C sites. In the first C site, C(5) is bonded in a distorted trigonal planar geometry to one N(1) and one H(3) atom. The C(5)-N(1) bond length is 1.36 Å. The C(5)-H(3) bond length is 1.09 Å. In the second C site, C(6) is bonded in a distorted trigonal planar geometry to one C(4), one N(1), and one H(4) atom. The C(6)-C(4) bond length is 1.38 Å. The C(6)-N(1) bond length is 1.36 Å. The C(6)-H(4) bond length is 1.08 Å. In the third C site, C(1) is bonded in a distorted single-bond geometry to one C(3) and one H(1) atom. The C(1)-C(3) bond length is 1.40 Å. The C(1)-H(1) bond length is 1.09 Å. In the fourth C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(1), and one O(3) atom. The C(2)-C(3) bond length is 1.51 Å. The C(2)-O(1) bond length is 1.27 Å. The C(2)-O(3) bond length is 1.27 Å. In the fifth C site, C(3) is bonded in a trigonal planar geometry to one C(1), one C(2), and one C(4) atom. The C(3)-C(4) bond length is 1.40 Å. In the sixth C site, C(4) is bonded in a distorted single-bond geometry to one C(3), one C(6), and one H(2) atom. The C(4)-H(2) bond length is 1.09 Å. N(1) is bonded in a trigonal planar geometry to one C(5), one C(6), and one O(2) atom. The N(1)-O(2) bond length is 1.31 Å. There are four 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(4) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(5) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(6) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one C(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ca(1) and one N(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one C(2) atom. Linkers: 4 [O]C(=O)c1cc[n+]([O-])cc1. Metal clusters: 2 [Ca]. The MOF has largest included sphere 1.70 A, density 1.78 g/cm3, surface area 3720.39 m2/g, accessible volume 0.07 cm3/g