Mn3C22H18(N2O7)2(H2O)2 crystallizes in the trigonal R-3 space group. The structure consists of eighteen water molecules inside a Mn3C22H18(N2O7)2 framework. In the Mn3C22H18(N2O7)2 framework, there are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in an octahedral geometry to one N(1), one N(2), one O(1), one O(5), one O(6), and one O(7) atom. The Mn(1)-N(1) bond length is 2.21 Å. The Mn(1)-N(2) bond length is 2.23 Å. The Mn(1)-O(1) bond length is 2.23 Å. The Mn(1)-O(5) bond length is 2.18 Å. The Mn(1)-O(6) bond length is 2.16 Å. The Mn(1)-O(7) bond length is 2.18 Å. In the second Mn site, Mn(2) is bonded in a distorted square co-planar geometry to two equivalent O(2) and two equivalent O(3) atoms. Both Mn(2)-O(2) bond lengths are 2.09 Å. Both Mn(2)-O(3) bond lengths are 2.02 Å. There are eleven inequivalent C sites. In the first C site, C(7) is bonded in a distorted single-bond geometry to one C(5) and one O(4) atom. The C(7)-C(5) bond length is 1.40 Å. The C(7)-O(4) bond length is 1.37 Å. In the second C site, C(8) is bonded in a distorted single-bond geometry to one C(5), one C(9), and one H(3) atom. The C(8)-C(5) bond length is 1.40 Å. The C(8)-C(9) bond length is 1.39 Å. The C(8)-H(3) bond length is 1.09 Å. In the third C site, C(9) is bonded in a distorted trigonal planar geometry to one C(2), one C(8), and one H(4) atom. The C(9)-C(2) bond length is 1.41 Å. The C(9)-H(4) bond length is 1.09 Å. In the fourth C site, C(10) is bonded in a distorted single-bond geometry to one C(11), one C(4), and one N(2) atom. The C(10)-C(11) bond length is 1.47 Å. The C(10)-C(4) bond length is 1.41 Å. The C(10)-N(2) bond length is 1.38 Å. In the fifth C site, C(11) is bonded in a distorted bent 120 degrees geometry to one C(10), one O(3), and one O(5) atom. The C(11)-O(3) bond length is 1.28 Å. The C(11)-O(5) bond length is 1.28 Å. In the sixth C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one N(2) atom. The C(1)-C(2) bond length is 1.47 Å. The C(1)-N(1) bond length is 1.36 Å. The C(1)-N(2) bond length is 1.36 Å. In the seventh C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(6), and one C(9) atom. The C(2)-C(6) bond length is 1.41 Å. In the eighth C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(1), and one O(2) atom. The C(3)-C(4) bond length is 1.47 Å. The C(3)-O(1) bond length is 1.28 Å. The C(3)-O(2) bond length is 1.29 Å. In the ninth C site, C(4) is bonded in a 3-coordinate geometry to one C(10), one C(3), and one N(1) atom. The C(4)-N(1) bond length is 1.37 Å. In the tenth C site, C(5) is bonded in a distorted trigonal planar geometry to one C(7), one C(8), and one H(1) atom. The C(5)-H(1) bond length is 1.09 Å. In the eleventh C site, C(6) is bonded in a distorted single-bond geometry to one C(2) and one H(2) atom. The C(6)-H(2) bond length is 1.09 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one C(1), and one C(4) atom. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Mn(1), one C(1), and one C(10) atom. There are nine inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(6) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(8) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(9) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(4) atom. The H(5)-O(4) bond length is 0.99 Å. In the sixth H site, H(6) is bonded in a distorted linear geometry to one O(5) and one O(6) atom. The H(6)-O(5) bond length is 1.62 Å. The H(6)-O(6) bond length is 1.01 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(7) atom. The H(7)-O(7) bond length is 0.99 Å. In the eighth H site, H(9) is bonded in a single-bond geometry to one O(7) atom. The H(9)-O(7) bond length is 0.98 Å. In the ninth H site, H(11) is bonded in a single-bond geometry to one O(6) atom. The H(11)-O(6) bond length is 0.98 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Mn(1) and one C(3) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(2) and one C(3) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one C(11) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one C(7) and one H(5) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Mn(1), one C(11), and one H(6) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mn(1), one H(11), and one H(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mn(1), one H(7), and one H(9) atom. Linkers: 4 [O]C(=O)C1=C(C([O])=O)N=C(c2cccc(O)c2)[N]1 ,2 [O]C(=O)[C]1N=C(c2cccc(O)c2)N=C1C([O])=O. Metal clusters: 9 [Mn]. The MOF has largest included sphere 5.69 A, density 1.48 g/cm3, surface area 3743.48 m2/g, accessible volume 0.29 cm3/g