{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T12:19:04Z","timestamp":1784809144425,"version":"3.55.0"},"reference-count":56,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T00:00:00Z","timestamp":1781049600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>This study investigates anion\u2013anion assemblies involving perhalate anions, XO4\u2212 (X = Cl, Br, I), in crystal structures retrieved from the Cambridge Structural Database to clarify the nature of the intermolecular interactions frequently interpreted as halogen bonds. Molecular electrostatic surface potential analysis demonstrates that isolated XO4\u2212 anions do not exhibit electrophilic \u03c3-holes on the halogen or oxygen atoms along the O\u2013X bond extensions, thereby precluding their role as conventional halogen- or chalcogen-bond donors. Gas-phase calculations further show that direct anion\u2013anion assemblies are intrinsically repulsive and unstable in isolation. However, when dielectric screening is introduced through implicit solvation models, metastable dimeric and oligomeric arrangements consistent with crystallographic motifs become accessible. Complementary QTAIM, IGMH, NBO, and SAPT analyses show that the observed X\u00b7\u00b7\u00b7O and O\u00b7\u00b7\u00b7O contacts are weak, environment-assisted anti-electrostatic interactions arising from a combination of dielectric screening, polarization, dispersion, and donor\u2013acceptor contributions. The results demonstrate that the structural organization of perhalate anions in crystalline environments is governed primarily by collective environmental and crystal-packing effects rather than intrinsic attractive interactions between isolated anions.<\/jats:p>","DOI":"10.3390\/ijms27125267","type":"journal-article","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T02:59:31Z","timestamp":1781146771000},"page":"5267","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Anti-Electrostatic Anion-Anion Noncovalent Interactions Are Not Halogen Bonds: Evidence from X\u00b7\u00b7\u00b7O Contacts in XO4\u2212 Dimers and Oligomers in Crystals Structures"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8779-789X","authenticated-orcid":false,"given":"Arpita","family":"Varadwaj","sequence":"first","affiliation":[{"name":"Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1, Tokyo 113-8656, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7102-3133","authenticated-orcid":false,"given":"Pradeep R.","family":"Varadwaj","sequence":"additional","affiliation":[{"name":"Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1, Tokyo 113-8656, Japan"},{"name":"Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toru\u0144, 87-100 Toru\u0144, Poland"},{"name":"Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1675-3835","authenticated-orcid":false,"given":"Helder M.","family":"Marques","sequence":"additional","affiliation":[{"name":"Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bogumi\u0142a","family":"Jezierska","sequence":"additional","affiliation":[{"name":"Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toru\u0144, 87-100 Toru\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5661-5659","authenticated-orcid":false,"given":"Ireneusz","family":"Grabowski","sequence":"additional","affiliation":[{"name":"Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toru\u0144, 87-100 Toru\u0144, Poland"},{"name":"Institute of Advanced Studies, Nicolaus Copernicus University in Toru\u0144, ul. Wile\u0144ska 4, 87-100 Toru\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohd. Mudassir","family":"Husain","sequence":"additional","affiliation":[{"name":"Department of Applied Sciences and Humanities, Faculty of Engineering and Technology, Jamia Millia Islamia, New Delhi 110025, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Koichi","family":"Yamashita","sequence":"additional","affiliation":[{"name":"Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1, Tokyo 113-8656, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Varadwaj, P.R., Marques, H.M., Varadwaj, A., Grabowski, I., and Yamashita, K. (2026). Molecular Electrostatic Surface Potential: A Predictive Framework for Noncovalent Interactions and Adsorption Characteristics in Molecular Entities. Int. J. Mol. Sci., 27.","DOI":"10.3390\/ijms27083352"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Varadwaj, P.R., Varadwaj, A., and Marques, H.M. (2019). Halogen Bonding: A Halogen-Centered Noncovalent Interaction Yet to Be Understood. Inorganics, 7.","DOI":"10.3390\/inorganics7030040"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"9760","DOI":"10.1021\/acs.jpca.3c06093","article-title":"Transition between the Noncovalency and Covalency of \u03c3\u2013Hole Bonds","volume":"127","author":"Scheiner","year":"2023","journal-title":"J. Phys. Chem. A"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"9274","DOI":"10.1039\/D2CC03191D","article-title":"Periodate anions as a halogen bond donor: Formation of anion\u22efanion dimers and other adducts","volume":"58","author":"Calabrese","year":"2022","journal-title":"Chem. Commun."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6654","DOI":"10.1039\/D3CS00479A","article-title":"Anion\u22efanion self-assembly under the control of \u03c3- and \u03c0-hole bonds","volume":"53","author":"Pizzi","year":"2024","journal-title":"Chem. Soc. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"11150","DOI":"10.1002\/anie.202003083","article-title":"\u201cAnti-Electrostatic\u201d Halogen Bonding","volume":"59","author":"Holthoff","year":"2020","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Weinhold, F. (2022). Anti-Electrostatic Pi-Hole Bonding: How Covalency Conquers Coulombics. Molecules, 27.","DOI":"10.3390\/molecules27020377"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"16530","DOI":"10.1002\/chem.202102549","article-title":"\u201cAnti-electrostatic\u201d Halogen Bonding between Ions of Like Charge","volume":"27","author":"Holthoff","year":"2021","journal-title":"Chem. Eur. J."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"19086","DOI":"10.1039\/D5NJ03660G","article-title":"\u201cAnti-electrostatic\u201d (inter-anion) chalcogen bonding interactions","volume":"49","author":"Yanbaeva","year":"2025","journal-title":"New J. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e202300298","DOI":"10.1002\/cphc.202300298","article-title":"Halogen Bonding Assembles Anion\u22c5\u22c5\u22c5Anion Architectures in Non-centrosymmetric Iodate and Bromate Crystals","volume":"24","author":"Calabrese","year":"2023","journal-title":"ChemPhysChem"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e202401030","DOI":"10.1002\/cphc.202401030","article-title":"Solid-State NMR Spectroscopy of Organic Periodates Featuring Halogen Bonded IO4\u2212\u2009\u22c5\u2009\u22c5\u2009\u22c5\u2009IO4\u2212 Adducts","volume":"26","author":"Beccaria","year":"2025","journal-title":"ChemPhysChem"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"14522","DOI":"10.1038\/ncomms14522","article-title":"NO3\u2212 anions can act as Lewis acid in the solid state","volume":"8","author":"Frontera","year":"2017","journal-title":"Nat. Commun."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e202402267","DOI":"10.1002\/chem.202402267","article-title":"Anions as Lewis Acids in Noncovalent Bonds","volume":"30","author":"Scheiner","year":"2024","journal-title":"Chem. Eur. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"e202500357","DOI":"10.1002\/cphc.202500357","article-title":"Does the Presence of Sigma Holes Affect the Way Neutral Ligands Attach to a Halonium Cation?","volume":"26","author":"Michalczyk","year":"2025","journal-title":"ChemPhysChem"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7748","DOI":"10.1039\/c004189k","article-title":"Halogen bonding: An electrostatically-driven highly directional noncovalent interaction","volume":"12","author":"Politzer","year":"2010","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"7005","DOI":"10.1021\/ja401420w","article-title":"Are Halogen Bonded Structures Electrostatically Driven?","volume":"135","author":"Stone","year":"2013","journal-title":"J. Am. Chem. Soc."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1007\/s00894-006-0130-2","article-title":"Halogen bonding: The \u03c3-hole","volume":"13","author":"Clark","year":"2007","journal-title":"J. Mol. Model."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Metrangolo, P., and Resnati, G. (2015). \u03c3-Hole Bonding: A Physical Interpretation. Halogen Bonding I: Impact on Materials Chemistry and Life Sciences, Springer International Publishing.","DOI":"10.1007\/978-3-319-14057-5"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"32166","DOI":"10.1039\/C7CP06793C","article-title":"The \u03c3-hole revisited","volume":"19","author":"Politzer","year":"2017","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1836","DOI":"10.1002\/jcc.25836","article-title":"Nature of halogen-centered intermolecular interactions in crystal growth and design: Fluorine-centered interactions in dimers in crystalline hexafluoropropylene as a prototype","volume":"40","author":"Varadwaj","year":"2019","journal-title":"J. Comput. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1002\/jcc.25125","article-title":"Do surfaces of positive electrostatic potential on different halogen derivatives in molecules attract? like attracting like!","volume":"39","author":"Varadwaj","year":"2018","journal-title":"J. Comput. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Varadwaj, P.R., Varadwaj, A., Marques, H.M., and Yamashita, K. (2018). Can Combined Electrostatic and Polarization Effects Alone Explain the F\u00b7\u00b7\u00b7F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective. Computation, 6.","DOI":"10.3390\/computation6040051"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"10257","DOI":"10.1073\/pnas.1810421115","article-title":"Revised M06 density functional for main-group and transition-metal chemistry","volume":"115","author":"Wang","year":"2018","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1165","DOI":"10.1142\/S0219633612500770","article-title":"Assessmnet of the performance of the M05-class and M0-6-class functionals for the structure and geometry of the hydrgen-bonded and halogne-bonded complexes","volume":"11","author":"Zhang","year":"2012","journal-title":"J. Theor. Comput. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"094106","DOI":"10.1063\/1.4867135","article-title":"Levels of symmetry adapted perturbation theory (SAPT). I. Efficiency and performance for interaction energies","volume":"140","author":"Parker","year":"2014","journal-title":"J. Chem. Phys."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"084114","DOI":"10.1063\/5.0275311","article-title":"Levels of symmetry-adapted perturbation theory (SAPT). II. Convergence of interaction energy components","volume":"163","author":"Schriber","year":"2025","journal-title":"J. Chem. Phys."},{"key":"ref_27","unstructured":"Chattaraj, P.K., and Chakraborty, D. (2021). Molecular Electrostatic Potentials: Significance and Applications. Chemical Reactivity in Confined Systems: Theory, Modelling and Applications, John Wiley & Sons Ltd."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1289\/ehp.8561191","article-title":"Molecular electrostatic potentials: An effective tool for the elucidation of biochemical phenomena","volume":"61","author":"Politzer","year":"1985","journal-title":"Environ. Health Perspect."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"899","DOI":"10.1021\/cr00088a005","article-title":"Intermolecular interactions from a natural bond orbital, donor-acceptor viewpoint","volume":"88","author":"Reed","year":"1988","journal-title":"Chem. Rev."},{"key":"ref_30","unstructured":"Bader, R.F.W. (1994). Atoms in Molecules: A Quantum Theory, Oxford University Press."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1002\/jcc.26812","article-title":"Independent gradient model based on Hirshfeld partition: A new method for visual study of interactions in chemical systems","volume":"43","author":"Lu","year":"2022","journal-title":"J. Comp. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"5494","DOI":"10.1021\/acs.cgd.4c00228","article-title":"Definition of the Halogen Bond (IUPAC Recommendations 2013): A Revisit","volume":"24","author":"Varadwaj","year":"2024","journal-title":"Cryst. Growth Des."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1711","DOI":"10.1351\/PAC-REC-12-05-10","article-title":"Definition of the halogen bond (IUPAC Recommendations 2013)","volume":"85","author":"Desiraju","year":"2013","journal-title":"Pure Appl. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1637","DOI":"10.1351\/PAC-REC-10-01-02","article-title":"Definition of the hydrogen bond (IUPAC Recommendations 2011)","volume":"83","author":"Arunan","year":"2011","journal-title":"Pure Appl. Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"e202506525","DOI":"10.1002\/ange.202506525","article-title":"Taxonomy of Chemical Bondings: Opportunities and Challenges","volume":"137","author":"Pizzi","year":"2025","journal-title":"Angew. Chem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"5233","DOI":"10.1039\/D3CE00400G","article-title":"Halogen bonding in chloroiodates(III)","volume":"25","author":"Korobeynikov","year":"2023","journal-title":"CrystEngComm"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"7184","DOI":"10.1039\/D3CP00379E","article-title":"Does a halogen bond require positive potential on the acid and negative potential on the base?","volume":"25","author":"Scheiner","year":"2023","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1889","DOI":"10.1515\/pac-2018-0713","article-title":"Definition of the chalcogen bond (IUPAC Recommendations 2019)","volume":"91","author":"Aakeroy","year":"2019","journal-title":"Pure Appl. Chem."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"7968","DOI":"10.1021\/ja00260a006","article-title":"Properties of atoms in molecules: Atomic volumes","volume":"109","author":"Bader","year":"1987","journal-title":"J. Am. Chem. Soc."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"24071","DOI":"10.1021\/acs.inorgchem.4c04734","article-title":"Transformation of Kagom\u00e9 and Breathing Kagom\u00e9 Lattices Induced by Ion Replacement","volume":"63","author":"He","year":"2024","journal-title":"Inorg. Chem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1107\/S1600536814024283","article-title":"Crystal structure of tin(II) perchlorate trihydrate","volume":"70","author":"Hennings","year":"2014","journal-title":"Acta Cryst. E"},{"key":"ref_42","unstructured":"(2026, March 25). The Cambridge Crystallographic Data Centre (CCDC). Available online: https:\/\/www.ccdc.cam.ac.uk\/solutions\/csd-core\/components\/csd\/."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1107\/S2052520616003954","article-title":"The Cambridge Structural Database","volume":"72","author":"Groom","year":"2016","journal-title":"Acta Cryst. B"},{"key":"ref_44","unstructured":"Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Barone, V., Petersson, G.A., and Nakatsuji, H. (2016). Gaussian 16 Rev. C.01, Gaussian, Inc."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1045","DOI":"10.1021\/ci600510j","article-title":"Basis Set Exchange: A Community Database for Computational Sciences","volume":"47","author":"Schuchardt","year":"2007","journal-title":"J. Chem. Inf. Model."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"4814","DOI":"10.1021\/acs.jcim.9b00725","article-title":"New Basis Set Exchange: An Open, Up-to-Date Resource for the Molecular Sciences Community","volume":"59","author":"Pritchard","year":"2019","journal-title":"J. Chem. Inf. Model."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"6378","DOI":"10.1021\/jp810292n","article-title":"Universal Solvation Model Based on Solute Electron Density and on a Continuum Model of the Solvent Defined by the Bulk Dielectric Constant and Atomic Surface Tensions","volume":"113","author":"Marenich","year":"2009","journal-title":"J. Phys. Chem. B"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"2999","DOI":"10.1021\/cr9904009","article-title":"Quantum Mechanical Continuum Solvation Models","volume":"105","author":"Tomasi","year":"2005","journal-title":"Chem. Rev."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1002\/wcms.19","article-title":"The electrostatic potential: An overview","volume":"1","author":"Murray","year":"2011","journal-title":"WIREs Comput. Mol. Sci."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"580","DOI":"10.1002\/jcc.22885","article-title":"Multiwfn: A multifunctional wavefunction analyzer","volume":"33","author":"Lu","year":"2012","journal-title":"J. Comp. Chem."},{"key":"ref_51","unstructured":"Keith, T.A. (2019). AimAll (V. 19.10.12), TK Gristmill Software. Available online: https:\/\/aim.tkgristmill.com."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"184108","DOI":"10.1063\/5.0006002","article-title":"Psi4 1.4: Open-source software for high-throughput quantum chemistry","volume":"152","author":"Smith","year":"2020","journal-title":"J. Chem. Phys."},{"key":"ref_53","first-page":"1792","article-title":"Natural Bond Orbital (NBO) Methods","volume":"Volume 3","author":"Schleyer","year":"1998","journal-title":"Encyclopedia of Computational Chemistry"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"2363","DOI":"10.1002\/jcc.23060","article-title":"Natural bond orbital analysis: A critical overview of relationships to alternative bonding perspectives","volume":"33","author":"Weinhold","year":"2012","journal-title":"J. Comp. Chem."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"1758","DOI":"10.1103\/PhysRevB.59.1758","article-title":"From ultrasoft pseudopotentials to the projector augmented-wave method","volume":"59","author":"Kresse","year":"1999","journal-title":"Phys. Rev. B"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"11169","DOI":"10.1103\/PhysRevB.54.11169","article-title":"Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set","volume":"54","author":"Kresse","year":"1996","journal-title":"Phys. Rev. B"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/27\/12\/5267\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T03:06:23Z","timestamp":1781147183000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/27\/12\/5267"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,10]]},"references-count":56,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["ijms27125267"],"URL":"https:\/\/doi.org\/10.3390\/ijms27125267","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,10]]}}}