Strong hydrogen-bonded amino acid dimers in L-alanine alaninium nitrate

The title compound, C3H7NO2.C3H8NO2+. NO3-, contains L-alanine-alaninium di mers bonded via the carboxyl groups by a strong asymmetric hydrogen bond wi th an O . . .O distance of 2.4547 (19) Angstrom. The neutral alanine molecu le exists as a zwitterion, where the carboxyl group is dissociated and the amino group is protonated. The alaninium cation has both groups in their ac idic form. The alanine molecule and the alaninium cation differ only slight ly in their conformation, having an N-C-alpha-C=O torsion angle close to -2 5 degrees. The dimers and the nitrate anion are joined through a three-dime nsional hydrogen-bond network, in which the full hydrogen-bonding capabilit ies of the amino groups of the two alanine moieties are realised.