YC12(O2Cl)4 crystallizes in the tetragonal I4_1/a space group. Y(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. All Y(1)-O(1) bond lengths are 2.31 Å. All Y(1)-O(2) bond lengths are 2.40 Å. There are three 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 Cl(1) atom. The C(1)-C(2) bond length is 1.34 Å. The C(1)-C(3) bond length is 1.40 Å. The C(1)-Cl(1) bond length is 1.73 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one C(1) and one O(1) atom. The C(2)-O(1) bond length is 1.28 Å. In the third C site, C(3) is bonded in a single-bond geometry to one C(1) and one O(2) atom. The C(3)-O(2) bond length is 1.25 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Y(1) and one C(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Y(1) and one C(3) atom. Cl(1) is bonded in a single-bond geometry to one C(1) atom. Linkers: 5 [O]C1=C(Cl)C(=O)C(=O)[C](Cl)C1=O. Metal clusters: 2 [Y]. The MOF has largest included sphere 5.67 A, density 0.98 g/cm3, surface area 3459.30 m2/g, accessible volume 0.61 cm3/g