SmH3(C5O4)2 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(12), one O(14), one O(16), one O(2), one O(6), and one O(8) atom. The Sm(1)-O(1) bond length is 2.47 Å. The Sm(1)-O(10) bond length is 2.34 Å. The Sm(1)-O(12) bond length is 2.45 Å. The Sm(1)-O(14) bond length is 2.37 Å. The Sm(1)-O(16) bond length is 2.31 Å. The Sm(1)-O(2) bond length is 2.43 Å. The Sm(1)-O(6) bond length is 2.40 Å. The Sm(1)-O(8) bond length is 2.53 Å. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one O(11), one O(13), one O(15), one O(3), one O(4), one O(5), one O(7), and one O(9) atom. The Sm(2)-O(11) bond length is 2.39 Å. The Sm(2)-O(13) bond length is 2.34 Å. The Sm(2)-O(15) bond length is 2.39 Å. The Sm(2)-O(3) bond length is 2.41 Å. The Sm(2)-O(4) bond length is 2.46 Å. The Sm(2)-O(5) bond length is 2.45 Å. The Sm(2)-O(7) bond length is 2.43 Å. The Sm(2)-O(9) bond length is 2.50 Å. There are twenty 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(4) atom. The C(1)-O(1) bond length is 1.25 Å. The C(1)-O(4) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(2) and one O(3) atom. The C(2)-O(2) bond length is 1.25 Å. The C(2)-O(3) bond length is 1.24 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(3)-O(5) bond length is 1.24 Å. The C(3)-O(6) bond length is 1.26 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(7) and one O(8) atom. The C(4)-O(7) bond length is 1.23 Å. The C(4)-O(8) bond length is 1.24 Å. In the fifth C site, C(5) is bonded in a bent 120 degrees geometry to one C(6), one O(10), and one O(9) atom. The C(5)-C(6) bond length is 1.52 Å. The C(5)-O(10) bond length is 1.25 Å. The C(5)-O(9) bond length is 1.25 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 1.37 Å. The C(6)-C(7) bond length is 1.38 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(1) atom. The C(7)-C(8) bond length is 1.39 Å. The C(7)-H(1) bond length is 0.93 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(12), one C(7), and one C(9) atom. The C(8)-C(12) bond length is 1.51 Å. The C(8)-C(9) bond length is 1.39 Å. In the ninth C site, C(9) is bonded in a distorted single-bond geometry to one C(10), one C(8), and one H(2) atom. The C(9)-C(10) bond length is 1.40 Å. The C(9)-H(2) 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(13), and one C(9) atom. The C(10)-C(11) bond length is 1.40 Å. The C(10)-C(13) bond length is 1.47 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(3) atom. The C(11)-H(3) bond length is 0.93 Å. In the twelfth C site, C(12) is bonded in a bent 120 degrees geometry to one C(8), one O(11), and one O(12) atom. The C(12)-O(11) bond length is 1.24 Å. The C(12)-O(12) bond length is 1.27 Å. In the thirteenth C site, C(13) is bonded in a trigonal planar geometry to one C(10), one C(14), and one C(18) atom. The C(13)-C(14) bond length is 1.39 Å. The C(13)-C(18) bond length is 1.39 Å. In the fourteenth C site, C(14) is bonded in a distorted single-bond geometry to one C(13), one C(15), and one H(4) atom. The C(14)-C(15) bond length is 1.39 Å. The C(14)-H(4) bond length is 0.93 Å. In the fifteenth C site, C(15) is bonded in a trigonal planar geometry to one C(14), one C(16), and one C(20) atom. The C(15)-C(16) bond length is 1.39 Å. The C(15)-C(20) bond length is 1.49 Å. In the sixteenth C site, C(16) is bonded in a distorted single-bond geometry to one C(15), one C(17), and one H(5) atom. The C(16)-C(17) bond length is 1.39 Å. The C(16)-H(5) bond length is 0.93 Å. In the seventeenth C site, C(17) is bonded in a trigonal planar geometry to one C(16), one C(18), and one C(19) atom. The C(17)-C(18) bond length is 1.38 Å. The C(17)-C(19) bond length is 1.49 Å. In the eighteenth C site, C(18) is bonded in a distorted single-bond geometry to one C(13), one C(17), and one H(6) atom. The C(18)-H(6) bond length is 0.93 Å. In the nineteenth C site, C(19) is bonded in a distorted bent 120 degrees geometry to one C(17), one O(15), and one O(16) atom. The C(19)-O(15) bond length is 1.26 Å. The C(19)-O(16) bond length is 1.25 Å. In the twentieth C site, C(20) is bonded in a distorted bent 120 degrees geometry to one C(15), one O(13), and one O(14) atom. The C(20)-O(13) bond length is 1.25 Å. The C(20)-O(14) bond length is 1.26 Å. There are six inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(7) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(9) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(11) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(14) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(16) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(18) atom. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Sm(1) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Sm(1) and one C(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Sm(2) and one C(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Sm(2) and one C(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Sm(2) and one C(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Sm(1) and one C(3) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Sm(2) and one C(4) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Sm(1) and one C(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Sm(2) and one C(5) atom. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Sm(1) and one C(5) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Sm(2) and one C(12) atom. In the twelfth O site, O(12) is bonded in a distorted bent 120 degrees geometry to one Sm(1) and one C(12) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Sm(2) and one C(20) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Sm(1) and one C(20) atom. In the fifteenth O site, O(15) is bonded in a bent 120 degrees geometry to one Sm(2) and one C(19) atom. In the sixteenth O site, O(16) is bonded in a distorted bent 150 degrees geometry to one Sm(1) and one C(19) atom. Linkers: 4 [O]C(=O)c1cc(C([O])=O)cc(-c2cc(C([O])=O)cc(C([O])=O)c2)c1 ,7 [O]C(=O)C([O])=O. Metal clusters: 8 [Sm]. The MOF has largest included sphere 4.26 A, density 1.96 g/cm3, surface area 2575.69 m2/g, accessible volume 0.17 cm3/g