The 1:1 proton-transfer compound of sulfanilamide with 3,5-dinitrosalicylic acid

The crystal structure of the proton-transfer compound from the reaction of 3,5-di­nitro­salicylic acid (DNSA) with sulfanil­amide (ABSA), i.e. 4-sulfon­amido­anilinium 3,5-di­nitro­salicyl­ate, C6H9N2O2S+·C7H3N2O7−, shows an extensively hydrogen-bonded polymeric structure in which the protonated amino group of sulfanil­amide together with the amide group give a total of eight intermolecular interactions with most of the O atoms of the DNSA anions [N⋯O 2.822 (2)–3.172 (2) Å], together with both of the sulfonate O atoms of adjacent ABSA cations [N⋯O 2.867 (2) and 3.090 (2) Å].