Crystal structures of nitron and its non-stoichiometric hydrochloride

The crystal structures of the hemi-ethanolate of nitron, C₂₀H₁₆N4(C₂H₆O)₀.₅, and of a non- stoichiometric hydrochloride of nitron, C₂₀Hi₆N4(HCl)1.7(H₂O)₃.₃, have been determined by X-ray diffraction from diffractometer data at 295 K and refined by block diagonal least squares to residuals of 0.069 (2049 ‘observed’ reflections) and 0.055 (1915), respectively. Crystals of the hemi-ethanolate of nitron are monoclinic P2₁/n, a 12.697(6), b 15.821(5), c 19.064(6) Å, β 108.79(3)°, Z 8. Crystals of the non-stoichiometric hydrochloride of nitron are also monoclinic C2/c, a 25.41(1), b 5.968(6), c 29.40(2) Å, β 103.53(5)°, Z 8. Despite some unusual features in their molecular geometry, these structures are consistent with the mesoionic character of nitron.