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The standard (p\u00b0 = 0.1 MPa) enthalpy of formation of crystalline guanidinium 5,5\u2032-azotetrazolate (GZT) (453.6 \u00b1 3.2 kJ\/mol) was determined experimentally using static-bomb combustion calorimetry and was found to be in good agreement with the literature\u2019s values. However, using the CBS-4M\/Jenkins method, the calculated enthalpy of formation of GZT was again in poor agreement with the experimentally determined value. The method we used recently to calculate the enthalpy of formation of TKX-50, based on the calculation of the heat of formation of the salt and of the corresponding neutral adduct, was then applied to GZT and provided excellent agreement with the experimentally determined value. Finally, in order to validate the findings, this method was also applied to predict the enthalpy of formation of a range of 1:1 and 2:1 salts (M+X\u2212 and (M+)2X2\u2212 salts, respectively), and the values obtained were comparable to experimentally determined values. The agreement using this approach was generally very good for both 1:1 and 2:1 salts; therefore, this approach provides a simple and reliable method which can be applied to calculate the enthalpy of formation of energetic C, H, N, O salts with much greater accuracy than the current, commonly used method.<\/jats:p>","DOI":"10.3390\/thermo3040033","type":"journal-article","created":{"date-parts":[[2023,10,5]],"date-time":"2023-10-05T09:21:27Z","timestamp":1696497687000},"page":"549-565","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Enthalpy of Formation of the Nitrogen-Rich Salt Guanidinium 5,5\u2032-Azotetrazolate (GZT) and a Simple Approach for Estimating the Enthalpy of Formation of Energetic C, H, N, O Salts"],"prefix":"10.3390","volume":"3","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6280-7975","authenticated-orcid":false,"given":"Ana L. R.","family":"Silva","sequence":"first","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o em Qu\u00edmica (CIQUP), Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre, P-4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6813-4492","authenticated-orcid":false,"given":"Gast\u00f3n P.","family":"Le\u00f3n","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o em Qu\u00edmica (CIQUP), Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre, P-4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0482-0308","authenticated-orcid":false,"given":"Maria D. M. C.","family":"Ribeiro da Silva","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o em Qu\u00edmica (CIQUP), Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre, P-4169-007 Porto, Portugal"}]},{"given":"Thomas M.","family":"Klap\u00f6tke","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Inorganic Chemistry, Small Molecule and Energetic Materials Research, LMU Munich, Butenandtstra\u00dfe 5-13, 81377 Munich, Germany"}]},{"given":"Jelena","family":"Reinhardt","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Inorganic Chemistry, Small Molecule and Energetic Materials Research, LMU Munich, Butenandtstra\u00dfe 5-13, 81377 Munich, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2023,10,5]]},"reference":[{"key":"ref_1","unstructured":"Klapotke, T.M. (2022). 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