{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T18:08:18Z","timestamp":1790186898258,"version":"4.1.0"},"reference-count":45,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T00:00:00Z","timestamp":1790121600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"\n Simplified theory is applied to predict\n \n \n \n \n \n \n \n NH<\/mml:mtext>\n 3<\/mml:mn>\n <\/mml:msub>\n \n OH<\/mml:mtext>\n +<\/mml:mo>\n <\/mml:msup>\n \u22ef<\/mml:mo>\n \n \n \n NO<\/mml:mtext>\n 3<\/mml:mn>\n <\/mml:msub>\n <\/mml:mrow>\n \u2212<\/mml:mo>\n <\/mml:msup>\n <\/mml:mrow>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:alternatives>\n <\/jats:inline-formula>\n contact ion pair (CIP) concentrations in electrolyte mixtures containing hydroxylammonium nitrate (HAN). The temperature range considered is\n \n \n \n \n \n 300<\/mml:mn>\n \u00a0<\/mml:mtext>\n K<\/mml:mi>\n \u2212<\/mml:mo>\n 523<\/mml:mn>\n \u00a0<\/mml:mtext>\n K<\/mml:mi>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:alternatives>\n <\/jats:inline-formula>\n . The theory considers HAN loadings in the condensed phase less than 1\n M<\/jats:italic>\n , 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.\n <\/jats:p>","DOI":"10.1371\/journal.pone.0358491","type":"journal-article","created":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T17:37:24Z","timestamp":1790185044000},"page":"e0358491","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Simplified theory to predict contact ion pair formation in electrolyte mixtures containing hydroxylammonium nitrate"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9271-9738","authenticated-orcid":true,"given":"Benjamin","family":"Shaw","sequence":"first","affiliation":[{"name":"University of California","place":["Davis, California, United States of America"],"department":["Mechanical and Aerospace Engineering Department"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,9,23]]},"reference":[{"key":"pone.0358491.ref001","doi-asserted-by":"crossref","DOI":"10.2172\/1374990","volume-title":"Technical report on hydroxylamine nitrate","author":"DG Harlow","year":"1998"},{"key":"pone.0358491.ref002","volume-title":"Preparation and Characterization of Several Liquid Propellants","author":"N Klein","year":"1983"},{"key":"pone.0358491.ref003","doi-asserted-by":"crossref","unstructured":"Jankovsky RS. HAN-based monopropellants assessment for spacecraft. In: AIAA Paper, 1996.","DOI":"10.2514\/6.1996-2863"},{"key":"pone.0358491.ref004","doi-asserted-by":"crossref","unstructured":"Meinhardt D, Brewster G, Christofferson S, Wucherer EJ. Development and testing of new HAN-based monopropellants in small rocket thrusters. In: AIAA Paper 98-4006; 1998.","DOI":"10.2514\/6.1998-4006"},{"key":"pone.0358491.ref005","doi-asserted-by":"crossref","unstructured":"Wucherer EJ, Christofferson S, Reed B. Assessment of high performance HAN monopropellants. In: AIAA Paper 2000-3872; 2000.","DOI":"10.2514\/6.2000-3872"},{"key":"pone.0358491.ref006","volume-title":"Atmospheric pressure studies of liquid propellant drops in hot flows","author":"RA Beyer","year":"1986"},{"key":"pone.0358491.ref007","volume-title":"Single droplet studies in a hot high pressure environment","author":"RA Beyer","year":"1986"},{"issue":"3","key":"pone.0358491.ref008","first-page":"333","article-title":"Combustion behavior of HAN-based systems","volume":"70","author":"DL Zhu","year":"1987","journal-title":"Combustion and Flame"},{"key":"pone.0358491.ref009","unstructured":"Lee TW, Tseng LK, Faeth GM. Structure of Pressure-Atomized Monopropellant Sprays. In: 25th JANNAF Combustion Meeting. Huntsville, AL, USA: NASA\/Marshall Space Flight Center; 1988."},{"issue":"3","key":"pone.0358491.ref010","first-page":"448","article-title":"Droplet combustion of HAN-based monopropellants","volume":"13","author":"C Call","year":"1997","journal-title":"Journal of Propulsion and Power"},{"issue":"7","key":"pone.0358491.ref011","first-page":"99","article-title":"Combustion characteristics of HAN-based mixtures","volume":"174","author":"M Farshchi","year":"2002","journal-title":"Combustion Science and Technology"},{"issue":"3","key":"pone.0358491.ref012","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1615\/IntJEnergeticMaterialsChemProp.2012004978","article-title":"Hydroxylammonium nitrate as green propellant: Decomposition and stability","volume":"11","author":"R Amrousse","year":"2012","journal-title":"International Journal of Energetic Materials and Chemical Propulsion"},{"issue":"2","key":"pone.0358491.ref013","doi-asserted-by":"crossref","first-page":"741","DOI":"10.1021\/acs.jpcb.5c04209","article-title":"On the implementation of chemical and physical ion pairing in electrolyte models","volume":"130","author":"GM Silva","year":"2026","journal-title":"J Phys Chem B"},{"key":"pone.0358491.ref014","volume-title":"Physical chemistry of electrolyte solutions: Modern aspects","author":"JMG Barthel","year":"1998"},{"key":"pone.0358491.ref015","doi-asserted-by":"crossref","DOI":"10.1007\/b114546","volume-title":"Modern electrochemistry: ionics","author":"JO Bockris","year":"1998","edition":"2"},{"key":"pone.0358491.ref016","volume-title":"Ion association","author":"C Davies","year":"1962"},{"issue":"1","key":"pone.0358491.ref017","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1016\/0010-2180(88)90088-0","article-title":"Thermal decomposition of energetic materials 29\u2014The fast thermal decomposition characteristics of a multicomponent material: liquid gun propellant 1845","volume":"74","author":"JT Cronin","year":"1988","journal-title":"Combustion and Flame"},{"key":"pone.0358491.ref018","doi-asserted-by":"crossref","unstructured":"Shaw BD, Williams FA. A model for the deflagration of aqueous solutions of hydroxylammonium nitrate. In: Twenty-Fourth Symposium (International) on Combustion. Pittsburgh, PA: The Combustion Institute; 1992. 1923\u201330.","DOI":"10.1016\/S0082-0784(06)80226-2"},{"issue":"41","key":"pone.0358491.ref019","doi-asserted-by":"crossref","first-page":"8086","DOI":"10.1021\/acs.jpca.8b05351","article-title":"Thermal Decomposition Mechanism of Aqueous Hydroxylammonium Nitrate (HAN): Molecular Simulation and Kinetic Modeling","volume":"122","author":"K Zhang","year":"2018","journal-title":"J Phys Chem A"},{"key":"pone.0358491.ref020","volume-title":"Thermal Decomposition Mechanism of Aqueous Hydroxylammonium Nitrate","author":"K Zhang","year":"2019"},{"issue":"23","key":"pone.0358491.ref021","doi-asserted-by":"crossref","first-page":"11421","DOI":"10.1021\/jp0571269","article-title":"Scaled particle theory study of the length scale dependence of cavity thermodynamics in different liquids","volume":"110","author":"G Graziano","year":"2006","journal-title":"J Phys Chem B"},{"key":"pone.0358491.ref022","doi-asserted-by":"crossref","first-page":"7736","DOI":"10.1021\/j100131a051","article-title":"Molecular Hard-Sphere Volume Increments","volume":"97","author":"D Ben-Amotz","year":"1993","journal-title":"The Journal of Physical Chemistry"},{"issue":"21","key":"pone.0358491.ref023","doi-asserted-by":"crossref","first-page":"4313","DOI":"10.1021\/jp970102k","article-title":"Real Ionic Solutions in the Mean Spherical Approximation. 2. Pure Strong Electrolytes up to Very High Concentrations, and Mixtures, in the Primitive Model","volume":"101","author":"J-P Simonin","year":"1997","journal-title":"J Phys Chem B"},{"issue":"1","key":"pone.0358491.ref024","first-page":"164","article-title":"Thermodynamics of the ionization of hydroxylamine in methanol-water and 1,4-dioxane-water","volume":"5","author":"FH Jumean","year":"1993","journal-title":"Asian Journal of Chemistry"},{"issue":"9","key":"pone.0358491.ref025","doi-asserted-by":"crossref","first-page":"1675","DOI":"10.1021\/ja01288a032","article-title":"Individual activity coefficients of ions in aqueous solutions","volume":"59","author":"J Kielland","year":"1937","journal-title":"J Am Chem Soc"},{"key":"pone.0358491.ref026","doi-asserted-by":"crossref","first-page":"112371","DOI":"10.1016\/j.fluid.2019.112371","article-title":"An empirical correlation for the relative permittivity of liquids in a wide temperature range: Application to the modeling of electrolyte systems with a GE\/EoS approach","volume":"506","author":"I Raspo","year":"2020","journal-title":"Fluid Phase Equilibria"},{"issue":"3","key":"pone.0358491.ref027","doi-asserted-by":"crossref","first-page":"824","DOI":"10.1021\/acs.jpcb.3c05623","article-title":"Liquid structure and hydrogen bonding in aqueous hydroxylammonium nitrate","volume":"128","author":"DD Depew","year":"2024","journal-title":"J Phys Chem B"},{"issue":"22","key":"pone.0358491.ref028","doi-asserted-by":"crossref","first-page":"14033","DOI":"10.1039\/D2CP01571D","article-title":"Structures, proton transfer and dissociation of hydroxylammonium nitrate (HAN) revealed by electrospray ionization tandem mass spectrometry and molecular dynamics simulations","volume":"24","author":"W Zhou","year":"2022","journal-title":"Phys Chem Chem Phys"},{"issue":"43","key":"pone.0358491.ref029","doi-asserted-by":"crossref","first-page":"17313","DOI":"10.1021\/acs.inorgchem.2c02932","article-title":"Direct observation of contact ion-pair formation in La3+ methanol solution","volume":"61","author":"P D\u2019Angelo","year":"2022","journal-title":"Inorg Chem"},{"issue":"51","key":"pone.0358491.ref030","doi-asserted-by":"crossref","first-page":"15652","DOI":"10.1021\/acs.jpcb.5b07492","article-title":"Structure and dynamics of NaCl ion pairing in solutions of water and methanol","volume":"119","author":"M Kelley","year":"2015","journal-title":"J Phys Chem B"},{"issue":"32","key":"pone.0358491.ref031","doi-asserted-by":"crossref","first-page":"4793","DOI":"10.1039\/b807090n","article-title":"Aqueous divalent metal-nitrate interactions: Hydration versus ion pairing","volume":"10","author":"M Xu","year":"2008","journal-title":"Phys Chem Chem Phys"},{"issue":"12","key":"pone.0358491.ref032","doi-asserted-by":"crossref","first-page":"124705","DOI":"10.1063\/5.0319762","article-title":"Theory of ion chemical potentials in heterogeneous electrolyte environments","volume":"164","author":"D Fraggedakis","year":"2026","journal-title":"J Chem Phys"},{"key":"pone.0358491.ref033","unstructured":"aqion. Hydrochemistry & Water Analysis. Software homepage for the free hydrochemistry tool aqion. 2025. Accessed 31 December 2025. https:\/\/www.aqion.de\/"},{"issue":"22","key":"pone.0358491.ref034","doi-asserted-by":"crossref","first-page":"227801","DOI":"10.1103\/PhysRevLett.108.227801","article-title":"Dielectric constant of ionic solutions: A field-theory approach","volume":"108","author":"A Levy","year":"2012","journal-title":"Phys Rev Lett"},{"issue":"16","key":"pone.0358491.ref035","doi-asserted-by":"crossref","first-page":"164909","DOI":"10.1063\/1.4826103","article-title":"Dipolar Poisson-Boltzmann approach to ionic solutions: A mean field and loop expansion analysis","volume":"139","author":"A Levy","year":"2013","journal-title":"J Chem Phys"},{"issue":"5","key":"pone.0358491.ref036","doi-asserted-by":"crossref","first-page":"054504","DOI":"10.1063\/1.5042235","article-title":"Dielectric constant of ionic solutions: Combined effects of correlations and excluded volume","volume":"149","author":"RM Adar","year":"2018","journal-title":"J Chem Phys"},{"issue":"12","key":"pone.0358491.ref037","doi-asserted-by":"crossref","first-page":"128007","DOI":"10.1103\/PhysRevLett.122.128007","article-title":"Contrasting dielectric properties of electrolyte solutions with polar and polarizable solvents","volume":"122","author":"DJ Grzetic","year":"2019","journal-title":"Phys Rev Lett"},{"key":"pone.0358491.ref038","doi-asserted-by":"crossref","first-page":"021501","DOI":"10.1103\/PhysRevE.81.021501","article-title":"Fluctuation in electrolyte solutions: The self energy","volume":"81","author":"Z-G Wang","year":"2010","journal-title":"Phys Rev E Stat Nonlin Soft Matter Phys"},{"issue":"9","key":"pone.0358491.ref039","first-page":"1","article-title":"Investigations on the association of ions. I. The influence of association of ions on the activity coefficients","volume":"7","author":"N Bjerrum","year":"1926","journal-title":"Kgl Danske Videnskabernes Selskab, Matematisk-Fysiske Meddelelser"},{"issue":"1","key":"pone.0358491.ref040","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1515\/zpch-1968-23847","article-title":"Zur theorie der bjerrumschen ionenassoziation in elektrolyten","author":"W Ebeling","year":"1968","journal-title":"Zeitschrift f\u00fcr Physikalische Chemie"},{"key":"pone.0358491.ref041","doi-asserted-by":"crossref","first-page":"967","DOI":"10.1039\/tf9343000967","article-title":"Distribution of ions in electrolytic solutions","volume":"30","author":"RM Fuoss","year":"1934","journal-title":"Trans Faraday Soc"},{"issue":"11","key":"pone.0358491.ref042","doi-asserted-by":"crossref","first-page":"4585","DOI":"10.1021\/cr040087x","article-title":"Ion pairing","volume":"106","author":"Y Marcus","year":"2006","journal-title":"Chemical Reviews"},{"issue":"9","key":"pone.0358491.ref043","doi-asserted-by":"crossref","first-page":"3858","DOI":"10.1063\/1.1669709","article-title":"Ion-Pair Theory of Concentrated Electrolytes. I. Basic Concepts","volume":"48","author":"FH Stillinger","year":"1968","journal-title":"The Journal of Chemical Physics"},{"issue":"23","key":"pone.0358491.ref044","doi-asserted-by":"crossref","first-page":"3826","DOI":"10.1103\/PhysRevLett.71.3826","article-title":"Criticality in ionic fluids: Debye-H\u00fcckel theory, Bjerrum, and beyond","volume":"71","author":"M Fisher","year":"1993","journal-title":"Phys Rev Lett"},{"issue":"19","key":"pone.0358491.ref045","doi-asserted-by":"crossref","first-page":"194904","DOI":"10.1063\/1.4982885","article-title":"Bjerrum pairs in ionic solutions: A Poisson-Boltzmann approach","volume":"146","author":"RM Adar","year":"2017","journal-title":"J Chem Phys"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0358491","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T17:37:39Z","timestamp":1790185059000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0358491"}},"subtitle":[],"editor":[{"given":"Hailing","family":"Ma","sequence":"first","affiliation":[{"name":"Monash University","place":["AUSTRALIA"]}],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,9,23]]},"references-count":45,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,9,23]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0358491","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,23]]}}}