PrC5O6(CH)2 crystallizes in the monoclinic P2_1/m space group. The structure consists of eight 02329_fluka molecules inside a PrC5O6 framework. In the PrC5O6 framework, there are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. The Pr(1)-O(5) bond length is 2.52 Å. The Pr(1)-O(6) bond length is 2.59 Å. The Pr(1)-O(7) bond length is 2.70 Å. Both Pr(1)-O(1) bond lengths are 2.49 Å. Both Pr(1)-O(3) bond lengths are 2.60 Å. Both Pr(1)-O(4) bond lengths are 2.50 Å. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one O(5), one O(6), one O(8), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Pr(2)-O(5) bond length is 2.58 Å. The Pr(2)-O(6) bond length is 2.52 Å. The Pr(2)-O(8) bond length is 2.70 Å. Both Pr(2)-O(2) bond lengths are 2.49 Å. Both Pr(2)-O(3) bond lengths are 2.50 Å. Both Pr(2)-O(4) bond lengths are 2.59 Å. There are six inequivalent C sites. In the first C site, C(7) is bonded in a distorted single-bond geometry to one O(5) atom. The C(7)-O(5) bond length is 1.32 Å. In the second C site, C(8) is bonded in a distorted single-bond geometry to one O(6) atom. The C(8)-O(6) bond length is 1.32 Å. In the third C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(3) atom. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(3) bond length is 1.30 Å. In the fourth C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(2) and one O(4) atom. The C(2)-O(2) bond length is 1.27 Å. The C(2)-O(4) bond length is 1.31 Å. In the fifth C site, C(3) is bonded in a distorted single-bond geometry to one O(7) atom. The C(3)-O(7) bond length is 1.39 Å. In the sixth C site, C(4) is bonded in a distorted single-bond geometry to one O(8) atom. The C(4)-O(8) bond length is 1.39 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Pr(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Pr(2) and one C(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Pr(1), one Pr(2), and one C(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Pr(1), one Pr(2), and one C(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Pr(1), one Pr(2), and one C(7) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Pr(1), one Pr(2), and one C(8) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Pr(1) and two equivalent C(3) atoms. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Pr(2) and two equivalent C(4) atoms. Linkers: 4 [O]C(=O)[C]1C=C([O])C=C(C([O])=O)O1. Metal clusters: 4 [Pr]. The MOF has largest included sphere 1.36 A, density 3.30 g/cm3, surface area 1361.86 m2/g, accessible volume 0.03 cm3/g