Mn5NiC52N4H20(O9Cl)2 crystallizes in the orthorhombic Fmmm space group. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 3-coordinate geometry to one O(5) and two equivalent O(3) atoms. The Mn(1)-O(5) bond length is 2.28 Å. Both Mn(1)-O(3) bond lengths are 2.08 Å. In the second Mn site, Mn(2) is bonded in an octahedral geometry to two equivalent O(5) and four equivalent O(4) atoms. Both Mn(2)-O(5) bond lengths are 2.34 Å. All Mn(2)-O(4) bond lengths are 2.14 Å. In the third Mn site, Mn(3) is bonded in a distorted trigonal bipyramidal geometry to two equivalent O(1), two equivalent O(2), and one Cl(1) atom. Both Mn(3)-O(1) bond lengths are 2.13 Å. Both Mn(3)-O(2) bond lengths are 2.09 Å. The Mn(3)-Cl(1) bond length is 2.33 Å. Ni(1) is bonded in a square co-planar geometry to two equivalent N(1) and two equivalent N(2) atoms. Both Ni(1)-N(1) bond lengths are 1.95 Å. Both Ni(1)-N(2) bond lengths are 2.00 Å. There are thirteen inequivalent C sites. In the first C site, C(1) is bonded in a distorted single-bond geometry to one C(2) and one H(1) atom. The C(1)-C(2) bond length is 1.43 Å. The C(1)-H(1) bond length is 0.93 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one N(1) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-N(1) bond length is 1.38 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(6) atom. The C(3)-C(4) bond length is 1.34 Å. The C(3)-C(6) bond length is 1.50 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one C(5), and one N(2) atom. The C(4)-C(5) bond length is 1.47 Å. The C(4)-N(2) bond length is 1.35 Å. In the fifth C site, C(5) is bonded in a distorted single-bond geometry to one C(4) and one H(2) atom. The C(5)-H(2) bond length is 0.93 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(11), one C(3), and one C(7) atom. The C(6)-C(11) bond length is 1.39 Å. The C(6)-C(7) bond length is 1.37 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(6), one C(8), and one H(3) atom. The C(7)-C(8) bond length is 1.40 Å. The C(7)-H(3) bond length is 0.93 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(13), one C(7), and one C(9) atom. The C(8)-C(13) bond length is 1.50 Å. The C(8)-C(9) bond length is 1.35 Å. In the ninth C site, C(9) is bonded in a distorted trigonal planar geometry to one C(10), one C(8), and one H(4) atom. The C(9)-C(10) bond length is 1.37 Å. The C(9)-H(4) bond length is 0.93 Å. In the tenth C site, C(10) is bonded in a trigonal planar geometry to one C(11), one C(12), and one C(9) atom. The C(10)-C(11) bond length is 1.36 Å. The C(10)-C(12) bond length is 1.52 Å. In the eleventh C site, C(11) is bonded in a distorted single-bond geometry to one C(10), one C(6), and one H(5) atom. The C(11)-H(5) bond length is 0.93 Å. In the twelfth C site, C(12) is bonded in a distorted bent 120 degrees geometry to one C(10), one O(1), and one O(2) atom. The C(12)-O(1) bond length is 1.25 Å. The C(12)-O(2) bond length is 1.24 Å. In the thirteenth C site, C(13) is bonded in a distorted bent 120 degrees geometry to one C(8), one O(3), and one O(4) atom. The C(13)-O(3) bond length is 1.22 Å. The C(13)-O(4) bond length is 1.24 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Ni(1) and two equivalent C(2) atoms. In the second N site, N(2) is bonded in a trigonal planar geometry to one Ni(1) and two equivalent C(4) atoms. There are five 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(5) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(7) 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 C(11) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mn(3) and one C(12) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(3) and one C(12) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mn(1) and one C(13) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mn(2) and one C(13) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Mn(1) and one Mn(2) atom. Cl(1) is bonded in a single-bond geometry to one Mn(3) atom. Linkers: 2 [O]C(=O)c1cc(cc(c1)C1=C2C=CC3=[N]2[Ni@]24n5c1ccc5C(=C1[N]2=C(C=C1)C(=c1n4c(=C3c2cc(cc(c2)C(=O)[O])C(=O)[O])cc1)c1cc(cc(c1)C(=O)[O])C(=O)[O])c1cc(cc(c1)C(=O)[O])C(=O)[O])C(=O)[O]. Metal clusters: 2 [C]1O[Mn]2O[C]O[Mn]34(O1)(O[C]O[Mn](O[C]O3)O4)O2 ,2 Cl[Mn]1234O[C]O[Mn]1(Cl)(O[C]O2)(O[C]O3)O[C]O4. RCSR code: scu. The MOF has largest included sphere 9.52 A, density 0.85 g/cm3, surface area 3800.19 m2/g, accessible volume 0.74 cm3/g