2-Phenyl-5-(trifluoro-meth-yl)pyrazol-3(2H)-one.

The title compound, C(10)H(7)F(3)N(2)O, is an analogue of pyrazolone derivatives with potential analgesic and anti-inflammatory properties. Its mol-ecular structure consists of phenyl and pyrazol-3(2H)-one units with a dihedral angle between the mean planes of the rings of 33.0 (1)°. The crystal structure is stabilized by an inter-molecular hydrogen bond between the N-H group and the carbonyl O atom of the pyrazol-3(2H)-one ring which links the mol-ecules into supra-molecular C(5) chains along [001] and by weak π-π stacking inter-actions between the phenyl rings [centroid-centroid distance = 3.881 (2) Å]. The F atoms are disordered over two positions with refined site occupancies of 0.768(11) and 0.232(11).