A structural and theoretical study of intermolecular interactions in nicotinohydrazide dihydrochloride.

In the title compound [systematic name: 3-(azaniumylcarbamoyl)pyridinium dichloride], C(6)H(9)N(3)O(2+)·2Cl(-), the ions are connected by N-H···Cl hydrogen bonds to form layers and C-H···Cl interactions expand the layers into a three-dimensional net. The energies of the N-H···Cl interactions range from typical for very weak interactions (0.17 kcal mol(-1)) to those observed for relatively strong interactions (29.1 kcal mol(-1)). C-H···Cl interactions can be classified as weak and mildly strong (energies ranging from 2.2 to 8.2 kcal mol(-1)). Despite the short contacts existing between the parallel aromatic rings of the cations, π-π interactions do not occur.