Hydrogen bonding and ring asymmetry in a substituted cyclopropane: (+)-trans-(1S,2S)-2-phenylcyclopropanecarboxylic acid at 208 K.

The title compound, C10H10O2, crystallized in space group P2(1) with two molecules in the asymmetric unit. In this structure, hydrogen bonding of the cyclic dimer type [with O ... O 2.623(2)-2.637(2)A] links the two molecules of the asymmetric unit. The two carboxylic H atoms are ordered, as are the O atoms. Each of the two non-equivalent molecules exhibits an asymmetric cyclopropane ring; the values found for the asymmetry parameters are delta(COOH) = -0.034(4) and -0.025(4)A, and delta(phenyl) = -0.028(4) and -0.023(4)A.