(IUCr) Crystallography Journals Online

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Acta Cryst. (2013). E69, o353-o354
[ doi:10.1107/S160053681300322X ]

Bis(3,5-diamino-4H-1,2,4-triazol-1-ium) 3,4-dioxocyclobutane-1,2-diolate

H.-K. Fun, W.-S. Loh, A. Johnson, S. Yousuf and E. Eno

Abstract: The asymmetric unit of the title compound, 2C₂H₆N₅⁺·C₄O₄^2-, contains two 3,5-diamino-4H-1,2,4-triazolium cations and one squarate dianion. The squaric acid molecule donated one H atom to each of the two 3,5-diamino-1,2,4-triazole molecules at their N atoms. The squaric acid dianion has four C-O bonds which are shorter than a normal single C-O bond (1.426 Å) and are slightly longer than a normal C=O bond (1.23 Å), which indicates the degree of electron delocalization in the dianion. In the crystal, the cations and dianions are linked by N-HN and N-HO hydrogen bonds into a three-dimensional network.