Zhang (2012). Experimental Crystal data

R factor = 0.058; wR factor = 0.142; data-to-parameter ratio = 12.2. In the title compound, C8H9N3O4, there are two molecules in the asymmetric unit, one of which is in the zwitterionic form. The zwitterion contains an intramolecular N—H O hydrogen bond and the other molecule contains both an intramolecular N—H O and an intramolecular O—H O hydrogen bond. In the crystal, N—H O and N—H N hydrogen bonds link the molecules, formimg a two-dimen-sional network parallel to (101). Related literature For the biological activities of salicylhydrazide derivatives, see: Bagchi et al. (2004); Thompson et al. (2004); Al-Mawsawi et al. (2007). For metal complexes involving derivatives of the titl