AlC4H3O5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 51°. Both Al(1)-O(2) bond lengths are 1.93 Å. Both Al(1)-O(3) bond lengths are 1.93 Å. Both Al(1)-O(5) bond lengths are 1.85 Å. In the second Al site, Al(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 51°. Both Al(2)-O(1) bond lengths are 1.93 Å. Both Al(2)-O(4) bond lengths are 1.91 Å. Both Al(2)-O(5) bond lengths are 1.86 Å. There are four 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 1.48 Å. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.28 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one C(3), and one H(1) atom. The C(2)-C(3) bond length is 1.34 Å. The C(2)-H(1) bond length is 1.09 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(2), one C(4), and one H(2) atom. The C(3)-C(4) bond length is 1.48 Å. The C(3)-H(2) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a bent 120 degrees geometry to one C(3), one O(3), and one O(4) atom. The C(4)-O(3) bond length is 1.28 Å. The C(4)-O(4) bond length is 1.27 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(3) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(5) atom. The H(3)-O(5) bond length is 0.97 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Al(2) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Al(1) and one C(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Al(1) and one C(4) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Al(2) and one C(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(2), and one H(3) atom. Linkers: 4 [O]C(=O)/C=C/C([O])=O. Metal clusters: 4 [Al]. RCSR code: lvt. The MOF has largest included sphere 5.46 A, density 1.10 g/cm3, surface area 3680.91 m2/g, accessible volume 0.51 cm3/g