The molecular structure of the title compound, 5,5-diphenyl-2-thioxoim
idazolidin-4-one, C15H12N2OS, resembles that of 5,5-diphenylhydantoin
(phenytoin). The C=S distance is 1.648 (2) Angstrom. The crystal struc
ture consists of ribbon-like infinite sheets of molecules bonded by N-
H ... O and N-H ... S hydrogen bonds. The packing of sheets is governe
d by van der Waals forces only.