CuH3(C2O)4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. The Cu(1)-O(5) bond length is 1.96 Å. The Cu(1)-O(6) bond length is 1.96 Å. The Cu(1)-O(7) bond length is 1.96 Å. The Cu(1)-O(8) bond length is 1.96 Å. In the second Cu site, Cu(2) is bonded in a linear geometry to one O(1) and one O(3) atom. The Cu(2)-O(1) bond length is 1.90 Å. The Cu(2)-O(3) bond length is 1.96 Å. There are sixteen inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.51 Å. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(2) bond length is 1.24 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(15), and one C(3) atom. The C(2)-C(15) bond length is 1.39 Å. The C(2)-C(3) bond length is 1.40 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(2), one C(5), and one H(1) atom. The C(3)-C(5) bond length is 1.40 Å. The C(3)-H(1) bond length is 1.01 Å. In the fourth C site, C(4) is bonded in a single-bond geometry to one C(14), one C(5), and one H(2) atom. The C(4)-C(14) bond length is 1.39 Å. The C(4)-C(5) bond length is 1.38 Å. The C(4)-H(2) bond length is 0.86 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(3), one C(4), and one C(6) atom. The C(5)-C(6) bond length is 1.50 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(11), one C(5), and one C(7) atom. The C(6)-C(11) bond length is 1.41 Å. The C(6)-C(7) bond length is 1.38 Å. In the seventh C site, C(7) is bonded in a single-bond geometry to one C(6) and one H(3) atom. The C(7)-H(3) bond length is 0.85 Å. In the eighth C site, C(8) is bonded in a single-bond geometry to one C(9) and one H(4) atom. The C(8)-C(9) bond length is 1.38 Å. The C(8)-H(4) bond length is 0.87 Å. In the ninth C site, C(9) is bonded in a trigonal planar geometry to one C(10), one C(16), and one C(8) atom. The C(9)-C(10) bond length is 1.38 Å. The C(9)-C(16) bond length is 1.50 Å. In the tenth C site, C(10) is bonded in a distorted single-bond geometry to one C(11), one C(9), and one H(5) atom. The C(10)-C(11) bond length is 1.39 Å. The C(10)-H(5) bond length is 0.93 Å. In the eleventh C site, C(11) is bonded in a trigonal planar geometry to one C(10), one C(12), and one C(6) atom. The C(11)-C(12) bond length is 1.50 Å. In the twelfth C site, C(12) is bonded in a distorted bent 120 degrees geometry to one C(11), one O(5), and one O(7) atom. The C(12)-O(5) bond length is 1.26 Å. The C(12)-O(7) bond length is 1.25 Å. In the thirteenth C site, C(13) is bonded in a distorted bent 120 degrees geometry to one C(14), one O(6), and one O(8) atom. The C(13)-C(14) bond length is 1.50 Å. The C(13)-O(6) bond length is 1.26 Å. The C(13)-O(8) bond length is 1.26 Å. In the fourteenth C site, C(14) is bonded in a trigonal planar geometry to one C(13), one C(15), and one C(4) atom. The C(14)-C(15) bond length is 1.39 Å. In the fifteenth C site, C(15) is bonded in a distorted single-bond geometry to one C(14), one C(2), and one H(6) atom. The C(15)-H(6) bond length is 0.85 Å. In the sixteenth C site, C(16) is bonded in a distorted bent 120 degrees geometry to one C(9), one O(3), and one O(4) atom. The C(16)-O(3) bond length is 1.28 Å. The C(16)-O(4) bond length is 1.25 Å. There are six inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(4) 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(8) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(10) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(15) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cu(2) and one C(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one C(1) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Cu(2) and one C(16) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one C(16) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one C(12) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Cu(1) and one C(13) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one C(12) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one C(13) atom. Linkers: 4 [O]C(=O)c1cc(C([O])=O)cc(-c2ccc(C([O])=O)cc2C([O])=O)c1. Metal clusters: 2 [C]1O[Cu]234O[C]O[Cu]2(O1)(O[C]O3)O[C]O4 ,4 O=[C]O[Cu]O[C]=O. The MOF has largest included sphere 6.82 A, density 1.34 g/cm3, surface area 3596.55 m2/g, accessible volume 0.37 cm3/g