title: (3E)-11,16-Dioxatricyclo-[15.4.0.0(5,10)]henicosa-1(21),3,5,7,9,17,19-heptaen-2-one.
abstract: The title compound, C19H18O3, crystallizes with three mol-ecules (A, B and C) in the asymmetric unit. The carbonyl O atom shows positional disorder over two sites in mol-ecules A and B; the site-occupancy ratios are 0.76 (3):0.24 (3) and 0.86 (3):0.14 (3), respectively. The ethyl-ene fragments in each mol-ecule have an E conformation, while the C-O-C-C torsion angles indicate near planarity. The dihedral angles formed by the aromatic rings are 20.0 (1), 23.7 (1) and 16.1 (1)° for mol-ecules A, B and C, respectively. Intra-molecular C-H⋯O hydrogen bonds occur in each mol-ecule.
authors.affiliation: Department of Physics, SMK Fomra Institute of Technology, Thaiyur, Chennai 603 103, India.
authors.forename: Gnanavelu
authors.initials: G
authors.lastname: Ganesh
authors.forename: Santhanagopalan
authors.initials: S
authors.lastname: Purushothaman
authors.forename: Piskala Subburaman
authors.initials: PS
authors.lastname: Kannan
authors.forename: Raghavachary
authors.initials: R
authors.lastname: Raghunathan
authors.forename: Arunachalathevar
authors.initials: A
authors.lastname: Subbiahpandi