Crystal structure and thermal behaviour of pyridinium styphnate

Abstract

In the crystal structure of the title molecular salt, C5H6N+·C6H2N3O8− (systematic name: pyridinium 3-hydroxy-2,4,6-trinitrophenolate), the pyridinium cation and the 3-hydroxy-2,4,6-trinitrophenolate anion are linked through bifurcated N—H...(O,O) hydrogen bonds, forming an R12(6) ring motif. The nitro group para with respect to phenolate ion forms an intramolecular hydrogen bond with the adjacent phenolic –OH group, which results in an S(6) ring motif. The nitro group flanked by the phenolate ion and the phenolic –OH group deviates noticeably from the benzene ring, subtending a dihedral angle of 89.2 (4)°. The other two nitro groups deviate only slightly from the plane of the benzene ring, making dihedral angles of 2.8 (4) and 3.4 (3)°. In the crystal, the 3-hydroxy-2,4,6-trinitrophenolate anions are linked through O—H...O hydrogen bonds, forming chains along [100]. These anionic chains, to which the cations are attached, are linked via C—H...O hydrogen bonds, forming a three-dimensional structure. Impact friction sensitivity tests and TGA/DTA studies on the title molecular salt imply that it is an insensitive high-energy-density material.

Keywords

• crystal structure
• pyridinium
• styphnate
• TGA/DTA studies
• hydrogen bonding