title: Tricyclo-[6.2.1.0]undeca-4,9-diene-3,6-dione.
abstract: The title compound, C(11)H(10)O(2), crystallizes with two independent mol-ecules in the asymmetric unit. In one mol-ecule, the dihedral angle between the mean planes of the C-C=C-C group of the diene unit and essentially planar cyclo-hexene ring is 51.07 (9)°, while in the other mol-ecule it is 54.49 (12)°. In the crystal structure, weak inter-molecular C-H⋯O inter-actions link the mol-ecules into columns along the b axis.
authors.affiliation: School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, 100044 Beijing, People's Republic of China.
authors.forename: Chongchen
authors.initials: C
authors.lastname: Wang