10,10-Dimethylanthrone

In the title compound, C16H14O, the asymmetric unit consists of three crystallographically independent molecules. The anthracene units are essentially planar, with maximum deviations of 0.165 (1), 0.153 (1) and 0.045 (1) Å in the three molecules. In the crystal structure, molecules are linked via intermolecular C—H⋯O hydrogen bonds. Further stabilization is provided by C—H⋯π interactions.

In the title compound, C 16 H 14 O, the asymmetric unit consists of three crystallographically independent molecules. The anthracene units are essentially planar, with maximum deviations of 0.165 (1), 0.153 (1) and 0.045 (1) Å in the three molecules. In the crystal structure, molecules are linked via intermolecular C-HÁ Á ÁO hydrogen bonds. Further stabilization is provided by C-HÁ Á Á interactions.

Experimental
The title compound was obtained as a gift sample from R. L. Fine Chem, Bangalore, India. X-ray quality crystals were obtained by slow evaporation from a methanol solution (m. p.: 349-352 K).

Refinement
All hydrogen atoms were positioned geometrically [C-H = 0.93 or 0.96Å] and were refined using a riding model, with U iso (H) = 1.2 or 1.5 U eq (C). A rotating group model was applied to the methyl groups.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.