Ca3C6(NO6)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms. The Ca(1)-O(3) bond length is 2.53 Å. The Ca(1)-O(5) bond length is 2.67 Å. There is one shorter (2.29 Å) and one longer (2.60 Å) Ca(1)-O(1) bond length. There is one shorter (2.40 Å) and one longer (2.54 Å) Ca(1)-O(2) bond length. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(12), one O(3), one O(4), one O(7), and one O(9) atom. The Ca(2)-O(10) bond length is 2.66 Å. The Ca(2)-O(11) bond length is 2.30 Å. The Ca(2)-O(12) bond length is 2.39 Å. The Ca(2)-O(3) bond length is 2.55 Å. The Ca(2)-O(4) bond length is 2.55 Å. The Ca(2)-O(7) bond length is 2.50 Å. The Ca(2)-O(9) bond length is 2.49 Å. In the third Ca site, Ca(3) is bonded in a distorted pentagonal pyramidal geometry to one O(10), one O(11), one O(12), one O(6), one O(8), and one O(9) atom. The Ca(3)-O(10) bond length is 2.34 Å. The Ca(3)-O(11) bond length is 2.54 Å. The Ca(3)-O(12) bond length is 2.55 Å. The Ca(3)-O(6) bond length is 2.45 Å. The Ca(3)-O(8) bond length is 2.61 Å. The Ca(3)-O(9) bond length is 2.37 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.50 Å. The C(1)-O(1) bond length is 1.24 Å. The C(1)-O(2) bond length is 1.24 Å. In the second C site, C(2) is bonded in a single-bond geometry to one C(1) atom. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(10), and one O(9) atom. The C(3)-C(4) bond length is 1.50 Å. The C(3)-O(10) bond length is 1.24 Å. The C(3)-O(9) bond length is 1.25 Å. In the fourth C site, C(4) is bonded in a single-bond geometry to one C(3) atom. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(11), and one O(12) atom. The C(5)-C(6) bond length is 1.50 Å. The C(5)-O(11) bond length is 1.24 Å. The C(5)-O(12) bond length is 1.24 Å. In the sixth C site, C(6) is bonded in a single-bond geometry to one C(5) atom. There are two inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one O(3), one O(4), and one O(5) atom. The N(1)-O(3) bond length is 1.30 Å. The N(1)-O(4) bond length is 1.30 Å. The N(1)-O(5) bond length is 1.30 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one O(6), one O(7), and one O(8) atom. The N(2)-O(6) bond length is 1.30 Å. The N(2)-O(7) bond length is 1.30 Å. The N(2)-O(8) bond length is 1.30 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Ca(1), one Ca(2), and one N(1) atom. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Ca(2) and one N(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Ca(1) and one N(1) atom. In the sixth O site, O(6) is bonded in a distorted L-shaped geometry to one Ca(3) and one N(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Ca(2) and one N(2) atom. In the eighth O site, O(8) is bonded in an L-shaped geometry to one Ca(3) and one N(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ca(2), one Ca(3), and one C(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ca(2), one Ca(3), and one C(3) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Ca(2), one Ca(3), and one C(5) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ca(2), one Ca(3), and one C(5) atom. Linkers: 8 [O][N+](=O)[O-] ,12 [C]C([O])=O. Metal clusters: 12 [Ca]. The MOF has largest included sphere 4.74 A, density 1.24 g/cm3, surface area 4532.08 m2/g, accessible volume 0.41 cm3/g