Borates or phosphates? That is the question

[EN] Chemical nomenclature is perceived to be a closed topic. However, this work shows that the identification of polyanionic groups is still ambiguous and so is the nomenclature for some ternary compounds. Two examples, boron phosphate (BPO4) and boron arsenate (BAsO4), which were assigned to the large phosphate and arsenate families, respectively, nearly a century ago, are explored. The analyses show that these two compounds should be renamed phosphorus borate (PBO4) and arsenic borate (AsBO4). Beyond epistemology, this has pleasing consequences at several levels for the predictive character of chemistry. It paves the way for future work on the possible syntheses of SbBO4 and BiBO4, and it also renders previous structure field maps completely predictive, allowing us to foresee the structure and phase transitions of NbBO4 and TaBO4. Overall, this work demonstrates that quantum mechanics calculations can contribute to the improvement of current chemical nomenclature. Such revisitation is necessary to classify compounds and understand their properties, leading to the main final aim of a chemist: predicting new compounds, their structures and their transformations. This research was partially supported by Spanish MINECO (grant Nos. MAT2015-71070-REDC and MAT2016-75586-C4-2-P, and MALTA Consolider Team RED2018-102612-T) and Generalitat Valenciana (grant No. PROMETEO/2018/123-EFIMAT). J. Contreras-Garci ' a thanks CALSIMLAB (public grant No. ANR-11-LABX-0037-01), overseen by the French National Research Agency (ANR) as part of the Investissements d'Avenir program (grant No. ANR-11-IDEX-0004-02). M. Marque ' s acknowledges support from the ERC grant `Hecate' and computational resources provided by the UKCP consortium under EPSRC grant EP/P022561/1. Contreras-García, J.; Izquierdo-Ruiz, F.; Marqués, M.; Manjón, F. (2020). Borates or phosphates? That is the question. Acta Crystallographica Section A: Foundations and Advances. 76:197-205. https://doi.org/10.1107/S2053273319016826 Abraham, R. H. & Marsden, J. E. (1994). Foundations of Mechanics. Reading: Addison Wesley. Alinger, N. L., Clark, T., Gasteiger, J., Kollman, P. A., Schaefer, H. F. III, Schreiner, P. R. & Schleyer, von R. (1998). Encyclopedia of Computational Chemistry, edited by R. F. W. Bader. Chichester: Wiley. Bader, R. F. W. (1990). Atoms in Molecules, a Quantum Theory. Oxford: Clarendon. Bader, R. F. W. (1994). Principle of stationary action and the definition of a proper open system. Physical Revi