CaC16N2H18O11 is Indium-like structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four CaC16N2H18O11 clusters. Ca(1) is bonded in a distorted pentagonal bipyramidal geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms. The Ca(1)-O(4) bond length is 2.39 Å. Both Ca(1)-O(1) bond lengths are 2.45 Å. Both Ca(1)-O(2) bond lengths are 2.41 Å. Both Ca(1)-O(6) bond lengths are 2.43 Å. There are eight inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one H(2) atom. The C(1)-C(2) bond length is 1.38 Å. The C(1)-N(1) bond length is 1.35 Å. The C(1)-H(2) bond length is 1.09 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one C(1), one C(3), and one H(3) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-H(3) bond length is 1.09 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(2), one C(4), and one C(8) atom. The C(3)-C(4) bond length is 1.40 Å. The C(3)-C(8) bond length is 1.52 Å. In the fourth C site, C(4) is bonded in a distorted single-bond geometry to one C(3), one C(5), and one H(4) atom. The C(4)-C(5) bond length is 1.38 Å. The C(4)-H(4) bond length is 1.09 Å. In the fifth C site, C(5) is bonded in a distorted trigonal planar geometry to one C(4), one N(1), and one H(5) atom. The C(5)-N(1) bond length is 1.35 Å. The C(5)-H(5) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted trigonal non-coplanar geometry to one N(1), one H(6), and one H(7) atom. The C(6)-N(1) bond length is 1.47 Å. The C(6)-H(6) bond length is 1.10 Å. The C(6)-H(7) bond length is 1.10 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(3) atom. The C(7)-O(1) bond length is 1.27 Å. The C(7)-O(3) bond length is 1.26 Å. In the eighth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(5), and one O(6) atom. The C(8)-O(5) bond length is 1.27 Å. The C(8)-O(6) bond length is 1.27 Å. N(1) is bonded in a trigonal planar geometry to one C(1), one C(5), and one C(6) atom. There are nine inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one C(1) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(4) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(5) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(6) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(6) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(2) atom. The H(8)-O(2) bond length is 0.99 Å. In the ninth H site, H(9) is bonded in a single-bond geometry to one O(2) and one O(5) atom. The H(9)-O(2) bond length is 1.00 Å. The H(9)-O(5) bond length is 1.69 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Ca(1) and one C(7) atom. In the second O site, O(2) is bonded in a distorted water-like geometry to one Ca(1), one H(8), and one H(9) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one C(7) atom. In the fourth O site, O(4) is bonded in a distorted water-like geometry to one Ca(1) and two equivalent H(1) atoms. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one C(8) and one H(9) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ca(1) and one C(8) atom. Linkers: 2 [O]C(=O)CN1[CH]C=C(C([O])=O)C=C1. Metal clusters: 2 O.O.O.[Ca].[O][C]=O.[O][C]=O.[O][C]=O.[O][C]=O. The MOF has largest included sphere 1.66 A, density 1.70 g/cm3, surface area 4394.98 m2/g, accessible volume 0.12 cm3/g