Abstract
A corrected and improved structure of the polymorph II of 2C3H8NO3 (+)·C2O4 (2-)·2H2O, based on single-crystal data, is presented. The structure is refined with anisotropic displacement parameters for all non-H atoms and all H atoms are located. Due to the charged moieties, the structure is classified as a mol-ecular salt. Inter-molecular O-H⋯O(-), O-H⋯O and N(+)-H⋯O(-)hydrogen bonds link the components of the structure. The l-serinium cations and oxalate anions form a network of channels in [100] direction, filled with the water molecules of crystallization. The dihedral angle between the CO2 units of the oxalate dianion is 10.2 (3)°