HoH5(C3O4)2 crystallizes in the triclinic P-1 space group. Ho(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Ho(1)-O(1) bond length is 2.39 Å. The Ho(1)-O(2) bond length is 2.36 Å. The Ho(1)-O(3) bond length is 2.30 Å. The Ho(1)-O(4) bond length is 2.28 Å. The Ho(1)-O(5) bond length is 2.28 Å. The Ho(1)-O(6) bond length is 2.45 Å. The Ho(1)-O(7) bond length is 2.45 Å. The Ho(1)-O(8) bond length is 2.34 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(2), one C(3), and one C(4) atom. The C(1)-C(2) bond length is 1.41 Å. The C(1)-C(3) bond length is 1.40 Å. The C(1)-C(4) bond length is 1.50 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(5) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-C(5) bond length is 1.51 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(1), one C(2), and one H(5) atom. The C(3)-H(5) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(1), and one O(4) atom. The C(4)-O(1) bond length is 1.28 Å. The C(4)-O(4) bond length is 1.26 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(5), and one O(6) atom. The C(5)-O(5) bond length is 1.26 Å. The C(5)-O(6) bond length is 1.28 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one O(7) and one O(8) atom. The C(6)-O(7) bond length is 1.28 Å. The C(6)-O(8) bond length is 1.25 Å. There are five inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(2) atom. The H(1)-O(2) bond length is 0.98 Å. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(1) and one O(3) atom. The H(2)-O(1) bond length is 1.67 Å. The H(2)-O(3) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(3) and one O(7) atom. The H(3)-O(3) bond length is 0.99 Å. The H(3)-O(7) bond length is 1.70 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(2) atom. The H(4)-O(2) bond length is 1.00 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(3) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ho(1), one C(4), and one H(2) atom. In the second O site, O(2) is bonded in a distorted water-like geometry to one Ho(1), one H(1), and one H(4) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Ho(1), one H(2), and one H(3) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Ho(1) and one C(4) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ho(1) and one C(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ho(1) and one C(5) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ho(1), one C(6), and one H(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ho(1) and one C(6) atom. Linkers: 1 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 2 [Ho]. RCSR code: flu. The MOF has largest included sphere 1.97 A, density 3.03 g/cm3, surface area 2035.95 m2/g, accessible volume 0.06 cm3/g