The extended "family" of B97-based density functional approximations: a comprehensive overview for DFT users and...

Density functional theory (DFT) has emerged as the most significant methodology in computational chemistry. However, the ever-growing number of density functional approximations (DFAs) has been a source of confusion to both users and developers. Particularly confusing is the extended "family" of DFAs based on B97, where many approaches have similar names but often differ in their underlying functional form. This review aims to be a succinct compendium of the family of B97-based DFAs and addresses both general and specialised audiences. 57 B97-based DFAs are comprehensively reviewed with a particular focus on the functional form and dispersion-corrected variants. Ambiguously named methods and common aliases are clarified. The general performance of B97-based methods in large-scale benchmarking studies on ground and excited state problems is summarised with the conclusion that B97M-V, ωB97M-V, and ωB97X-V (including other dispersion-corrected forms of these functionals) as well as ωB97M(2) are some of the currently most accurate DFT methods. It is our hope that this review clarifies the current state of the B97 family which is of relevance for DFT users and developers alike, particularly as development for this DFA family is ongoing.