(S)-Alanine–(S)-2-phen­oxy­propionic acid (1/1)

In the title co-crystal, C(3)H(7)NO(2)·C(9)H(10)O(3), the (S)-alanine mol­ecule exists in the zwitterionic form stabilized by two pairs of N(+)—H⋯O(−) hydrogen bonds and an electrostatic inter­action 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(−) [R (2) (2)(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.