Fluoren-9-one oxime

In the title mol­ecule, C(13)H(9)NO, the fluorene system and the oxime group non-H atoms are essentially coplanar, with a maximum deviation from the fluorene mean plane of 0.079 (2) Å for the oxime O atom. A short intra­molecular C—H⋯O generates an S(6) ring. In the crystal, mol­ecules related by a twofold screw axis are connected by O—H⋯N hydrogen bonds, forming [100] chains Within these chains, mol­ecules related by a unit translation along [100] show π–π stacking inter­actions between their fluorene ring systems with an inter­planar distance of 3.347 (2) Å. The dihedral angle between the fluorene units of adjacent mol­ecules along the helix is 88.40 (2)°. There is a short C—H⋯π contact between the fluorene groups belonging to neighbouring chains.