Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(C±C) = 0.004 A Ê R factor = 0.036 wR factor = 0.090 Data-to-parameter ratio = 7.4For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e. # 2002 International Union of Crystallography Printed in Great Britain ± all rights reserved The title salt, l-HisH 2 2+ Á2NO 3 À , contains two nitrate anions and one l-histidinium dication. The anions and cations are linked to each other through strong hydrogen bonds, formed by all H atoms covalently bonded to the N and O atoms of the l-histidinium dications. This three-dimensional complex network of hydrogen bonds ensures the cohesion of the ionic structure.

Key indicatorsSingle-crystal X-ray study T = 120 K Mean '(C±C) = 0.002 A Ê Disorder in solvent or counterion R factor = 0.036 wR factor = 0.105 Data-to-parameter ratio = 22.4 For details of how these key indicators were automatically derived from the article, see

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(C±C) = 0.002 A Ê R factor = 0.040 wR factor = 0.112 Data-to-parameter ratio = 11.1 For details of how these key indicators were automatically derived from the article, see

Key indicatorsSingle-crystal X-ray study T = 223 K Mean '(C±C) = 0.003 A Ê R factor = 0.036 wR factor = 0.140 Data-to-parameter ratio = 11.8For details of how these key indicators were automatically derived from the article, see