THE CRYSTAL AND MOLECULAR STRUCTURE OF BENZANILIDE

The crystal structure of benzanilide has been determined from Weissenberg photographs using Cu Kα radiations and refined to an R value of 0.075 for 766 independent reflections. The crystals are monoclinic, space group C2/c, Z=4, with a=24.34(4), b=5.325(3), c=8.012(8) A, β=107.2(3)°, Dm=1.32 and Dx=1.321 g cm−3. Dihedral angle between the benzene rings is 62.6°, and each benzene ring makes dihedral angle of 31.3 and 31.6° with the plane of amido group as found in Kevlar and Nomex polymers. The molecules related by a b-translation are linked together by N–H…O hydrogen bond [N…O 3.112(6), H…O 2.03 A, N–H…O 157°] to form a chain along b. The chains are held together primarily by dipole forces of carbonyl groups of the molecules related by inversion centers to form a sheet parallel to the bc plane. The sheets are stacked along a with disorder by van der Waals interactions.