NiC4N2H2SO5 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in an octahedral geometry to one N(1), one N(4), one O(1), one O(3), one O(5), and one O(9) atom. The Ni(1)-N(1) bond length is 2.07 Å. The Ni(1)-N(4) bond length is 2.04 Å. The Ni(1)-O(1) bond length is 2.05 Å. The Ni(1)-O(3) bond length is 2.04 Å. The Ni(1)-O(5) bond length is 2.04 Å. The Ni(1)-O(9) bond length is 2.08 Å. In the second Ni site, Ni(2) is bonded in an octahedral geometry to one N(2), one N(3), one O(10), one O(4), one O(6), and one O(8) atom. The Ni(2)-N(2) bond length is 2.05 Å. The Ni(2)-N(3) bond length is 2.06 Å. The Ni(2)-O(10) bond length is 2.02 Å. The Ni(2)-O(4) bond length is 2.09 Å. The Ni(2)-O(6) bond length is 2.06 Å. The Ni(2)-O(8) bond length is 2.07 Å. There are eight inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one N(1) atom. The C(2)-N(1) bond length is 1.34 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one N(2) atom. The C(3)-N(2) bond length is 1.34 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(4)-O(3) bond length is 1.26 Å. The C(4)-O(4) bond length is 1.28 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(6), and one O(7) atom. The C(5)-C(6) bond length is 1.50 Å. The C(5)-O(6) bond length is 1.29 Å. The C(5)-O(7) bond length is 1.25 Å. In the sixth C site, C(6) is bonded in a distorted single-bond geometry to one C(5), one C(7), and one N(3) atom. The C(6)-C(7) bond length is 1.42 Å. The C(6)-N(3) bond length is 1.34 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(6) and one N(4) atom. The C(7)-N(4) bond length is 1.34 Å. In the eighth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one O(8) and one O(9) atom. The C(8)-O(8) bond length is 1.26 Å. The C(8)-O(9) bond length is 1.28 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Ni(1), one C(2), and one S(1) atom. The N(1)-S(1) bond length is 1.64 Å. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Ni(2), one C(3), and one S(1) atom. The N(2)-S(1) bond length is 1.64 Å. In the third N site, N(3) is bonded in a trigonal planar geometry to one Ni(2), one C(6), and one S(2) atom. The N(3)-S(2) bond length is 1.63 Å. In the fourth N site, N(4) is bonded in a distorted trigonal planar geometry to one Ni(1), one C(7), and one S(2) atom. The N(4)-S(2) bond length is 1.64 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(5) and one O(6) atom. The H(1)-O(5) bond length is 1.00 Å. The H(1)-O(6) bond length is 1.67 Å. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(2) and one O(5) atom. The H(2)-O(2) bond length is 1.68 Å. The H(2)-O(5) bond length is 1.00 Å. In the third H site, H(3) is bonded in a distorted single-bond geometry to one O(10) and one O(7) atom. The H(3)-O(10) bond length is 1.00 Å. The H(3)-O(7) bond length is 1.65 Å. In the fourth H site, H(4) is bonded in a distorted linear geometry to one O(1) and one O(10) atom. The H(4)-O(1) bond length is 1.62 Å. The H(4)-O(10) bond length is 1.00 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in an L-shaped geometry to one N(1) and one N(2) atom. In the second S site, S(2) is bonded in an L-shaped geometry to one N(3) and one N(4) atom. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ni(1), one C(1), and one H(4) atom. In the second O site, O(2) is bonded in a distorted water-like geometry to one C(1) and one H(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Ni(1) and one C(4) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ni(2) and one C(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ni(1), one H(1), and one H(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ni(2), one C(5), and one H(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one C(5) and one H(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ni(2) and one C(8) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Ni(1) and one C(8) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ni(2), one H(3), and one H(4) atom. Linkers: 4 [O]C(=O)c1nsnc1C([O])=O. Metal clusters: 4 [Ni]. The MOF has largest included sphere 1.64 A, density 2.49 g/cm3, surface area 2643.62 m2/g, accessible volume 0.04 cm3/g