Naming Matters: Hydridic Hydrogen Atoms are Halogen, Chalcogen, and Pnictogen Bond Acceptors not "Hydridic Hydrogen...

The definition and classification of noncovalent interactions are essential for consistent communication in supramolecular chemistry. A recent paper introduced the term "hydridic hydrogen bond" to describe interactions where hydrogen atoms bound to electropositive elements (e.g., Si, Ge, Sn) act as electron donors. However, such terminology conflicts with IUPAC definition, which requires hydrogen to be bonded to more electronegative atoms for a hydrogen bond (HB). Herein, we combine electrostatic potential analysis, energy decomposition, ELF/QTAIM, and NBO calculations to show that interactions involving hydridic hydrogen atoms as donors and heavier main group elements (Br, Se, As) as acceptors are better classified as halogen, chalcogen, and pnictogen bonds (PnBs), respectively. Our results confirm the nucleophilic character of hydridic hydrogen atoms and the electrophilic role of the interacting elements via σ- and π-hole interactions, consistent with established IUPAC definitions. Experimental evidence from NMR supports this classification. By clarifying these interactions' nature and directionality, we advocate for nomenclature that aligns with chemical intuition and community standards, thereby avoiding confusion caused by unnecessary redefinitions.