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We evaluated the performance of several exchange\u2013correlation functionals, including PBEsol, NCAPR (Nearly Correct Asymptotic Potential Revised), SCAN (Strongly Constrained and Appropriately Normed), and PBE+U (Perdew\u2013Burke\u2013Ernezerhof + Hubbard U), to determine their ability to resolve electron donor and acceptor capacities. Our results demonstrated that local softness is a powerful tool for distinguishing non-equivalent metallic centers and coexisting oxidation states. Crucially, we found that the PBE+U functional, utilizing site-specific Hubbard parameters (U) calculated via density functional perturbation theory, is the most robust approach, consistently reproducing the expected one-electron transfer. This study highlights the necessity of integrating local reactivity descriptors with differentiated Hubbard corrections for the accurate design and characterization of redox-active functional materials.<\/jats:p>","DOI":"10.1063\/5.0342191","type":"journal-article","created":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T14:22:04Z","timestamp":1791901324000},"update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Local chemical softness as a reactivity probe in mixed-valence compounds of class I and class II (Cr2F5 and Co3O4): The importance of site-dependent Hubbard U parameters"],"prefix":"10.1063","volume":"165","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-1084-4469","authenticated-orcid":false,"given":"Josseline","family":"Aguilar-L\u00f3pez","sequence":"first","affiliation":[{"name":"Departamento de Qu\u00edmica, Universidad Aut\u00f3noma Metropolitana-Iztapalapa , Apartado Postal, 55-53409340 Iztapalapa, CDMX,","place":["Mexico"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9033-9168","authenticated-orcid":false,"given":"Guadalupe","family":"Castro","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica, Universidad Aut\u00f3noma Metropolitana-Iztapalapa , Apartado Postal, 55-53409340 Iztapalapa, CDMX,","place":["Mexico"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8898-749X","authenticated-orcid":false,"given":"Marcelo","family":"Galv\u00e1n","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica, Universidad Aut\u00f3noma Metropolitana-Iztapalapa , Apartado Postal, 55-53409340 Iztapalapa, CDMX,","place":["Mexico"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"317","published-online":{"date-parts":[[2026,10,13]]},"reference":[{"key":"2026101310210101300_c1","doi-asserted-by":"publisher","first-page":"1793","DOI":"10.1021\/cr990029p","article-title":"Conceptual density functional theory","volume":"103","year":"2003","journal-title":"Chem. 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