C3H7NO2C9H10O3

R factor = 0.029; wR factor = 0.081; data-to-parameter ratio = 16.0. In the title co-crystal, C3H7NO2C9H10O3, the (S)-alanine molecule exists in the zwitterionic form stabilized by two pairs of N+—H O hydrogen bonds and an electrostatic inter-action between the ammonium center and the carboxylate anion, forming a sheet along the ab plane. The carboxyl group of the (S)-2-phenoxypropionic acid molecule is connected to the top and bottom of the sheet via N+—H O C and O— H O [R22(7) graph set] hydrogen bonds, giving an (S,S)-homochiral layer, in which both methyl groups of (S)-alanine and the phenyl rings of (S)-2-phenoxypropionic acid are oriented in the same direction along the b axis. Related literature For the use of a chiral resolution agents, see: Hasegawa et al. (1998). For the crystal structure of enantiomeric and racemi