Patent ID: 8188136

Claim:
A process for preparing the crystalline modification V comprising: i) preparing a solution of a solid form of fipronil being different from the crystalline modification V in a solvent S selected from dimethylsulfoxide at a temperature of 100° C. to 150° C. or acetonitrile at a temperature of 60° C. to 81° C.; ii) effecting crystallization of fipronil from the hot solution; and iii) isolating the resulting precipitate; wherein said crystalline modification shows, in an X-ray powder diffractogram recorded using Cu—Kα radiation at 25° C., at least 3 of the following reflexes: 2θ=10.3±0.2° (1) 2θ=11.1±0.2° (2) 2θ=13.0±0.2° (3) 2θ=16.2±0.2° (4) 2θ=20.3±0.2° (5) 2θ=31.5±0.2°. (6)