Cocrystal of cis- and trans-N-phenylformamide.

N-Phenylformamide, C(7)H(7)NO, crystallizes with two molecules in the asymmetric unit which have different conformations of the formylamino group, one being cis and the other trans. This is the first example of an arylformamide crystal containing both conformational isomers and it may thus be considered a cocrystal of the two conformers. The two molecules in the unit cell are linked through N-H...O hydrogen bonding to two other molecules, thereby forming hydrogen-bonded tetramers within the crystal structure.