The crystal structure of triphenylbismuth has been determined from three-dimensional X-ray data measured with a linear diffractometer. The crystals are monoclinic, space group C2/c, with eight molecules of C18H15Bi in a unit cell of dimensions a= 27·70, b= 5·82, c= 20·45 Å, and β= 114·48°. The structure was solved by the heavy atom method and refined by least-squares methods to a final R of 0·069 over 1353 independent reflexions. The molecule is pyramidal but possesses no overall symmetry owing to the unequal rotations of the benzene rings about the Bi–C bonds. The mean Bi–C distance is 2·24 Å, and the mean C–Bi–C bond angle is 94°.