l-Glutamic acid hydro-chloride at 153 K.

THE TITLE COMPOUND [SYSTEMATIC NAME: (S)-1,3-dicarboxy-propanaminium chloride], C(5)H(10)NO(4) (+)·Cl(-), has been investigated previously by Dawson [Acta Cryst. (1953). 6, 81-83], with R = 0.106 and without the location of H atoms, and then by Sequeira, Rajagopal & Chidambaram [Acta Cryst. (1972). B28, 2514-2519] using neutron diffraction with R = 0.043. The present determination at 153 K has R = 0.017 and all the H atoms are located. There are obvious differences in some C-C bond lengths between the present and previous studies. In the present structure, l-glutamic acid is protonated and is linked to the Cl(-) anion by an O-H⋯Cl hydrogen bond. The crystal structure is established by a three-dimensional network of O-H⋯O, N-H⋯O and N-H⋯Cl hydrogen bonds.