Simplified theory to predict contact ion pair formation in electrolyte mixtures containing hydroxylammonium nitrate.

Simplified theory is applied to predict NH3OH+⋯NO3- contact ion pair (CIP) concentrations in electrolyte mixtures containing hydroxylammonium nitrate (HAN). The temperature range considered is 300 K-523 K. The theory considers HAN loadings in the condensed phase less than 1 M, which is where some experiments to investigate aqueous HAN decomposition kinetics have been performed. It is found that when HAN is mixed with methanol or ethanol, CIP concentrations can peak at small nonzero levels of the initial HAN loading, while HAN-water mixtures are predicted to not exhibit such CIP concentration peaks. These results are relevant to increasing understanding of conditions under which chemical reactivity as well as thermodynamic and transport properties may be influenced by the presence of CIPs.