Sanjuan-Szklarz, W. FabiolaW. FabiolaSanjuan-SzklarzWoińska, MagdalenaMagdalenaWoińskaDomagała, SławomirSławomirDomagałaDominiak, Paulina M.Paulina M.DominiakGrabowsky, SimonSimonGrabowsky0000-0002-3377-9474Jayatilaka, DylanDylanJayatilakaGutmann, MatthiasMatthiasGutmannWoźniak, KrzysztofKrzysztofWoźniak2024-09-022024-09-022020-07-28https://boris-portal.unibe.ch/handle/20.500.12422/39302X-ray diffraction is the main source of three-dimensional structural information.In total, more than 1.5 million crystal structures have been refined and depositedin structural databanks (PDB, CSD and ICSD) to date. Almost 99.7% of themwere obtained by approximating atoms as spheres within the independent atommodel (IAM) introduced over a century ago. In this study, X-ray datasets forsingle crystals of hydrated-oxalic acid were refined using several alternativeelectron density models that abandon the crude spherical approximation: themultipole model (MM), the transferable aspherical atom model (TAAM) andthe Hirshfeld atom refinement (HAR) model as a function of the resolution ofX-ray data. The aspherical models (MM, TAAM, HAR) give far more accurateand precise single-crystal X-ray results than IAM, sometimes identical to resultsobtained from neutron diffraction and at low resolution. Hence, asphericalapproaches open new routes for improving existing structural informationcollected over the last century.en500 - Science::570 - Life sciences; biology500 - Science::540 - Chemistryarticle10.48350/1506113293928410.1107/S2052252520010441