1-Methoxy-11H-benzo[b]fluoren-11-one

In the title compound, C18H12O2, the non-H atoms are nearly coplanar, the maximum atomic deviation being 0.113 (2) Å. π–π stacking is observed in the crystal structure, the shortest centroid–centroid distance being 3.5983 (19) Å. The molecular packing is further stabilized by weak C—H⋯O hydrogen bonds, forming an infinite chain along [100] and generating a C(6) motif.

In the title compound, C 18 H 12 O 2 , the non-H atoms are nearly coplanar, the maximum atomic deviation being 0.113 (2) Å .

Experimental
The title compound was synthesized according to the literature (Tang et al., 2011). Yellow parallelepiped-shaped crystals suitable for the crystallographic studies reported here were isolated over a period of six weeks by slow evaporation from a chloroform solution.

Refinement
The C bound H atoms were positioned geometrically (C-H = 0.93-0.96 Å) and allowed to ride on their parent atoms, with U iso (H) = 1.2U eq (C).  The molecular structure of the title compound, showing 50% probability displacement ellipsoids.

Figure 2
A section of the crystal packing of the title compound, viewed down the c axis. Blue and green dashed lines denote the intermolecular C7-H7···O1 and C11-H11···O1 hydrogen bonds, respectively.  (7) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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 > σ(F 2 ) is used only for calculating R-factors(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1