The terminology used to describe the central species in coordination chemistry remains inconsistent across major inorganic and general textbooks. While the IUPAC definition unifies this concept under the term “central atom”, many educational resources continue to alternate between central atom and central ion. This dual usage could create conceptual confusion where the metal center remains an isolated ion even after complexation. Quantum-chemical analyses (e.g., Mulliken calculations) reveal, however, that electron density redistribution during coordination prevents the metal from retaining its ionic character. To address this pedagogical argument, this study advocates for the exclusive use of a “central atom”, emphasizing that a “central atom” denotes the positional identity of the metal. Adopting consistent terminology will align chemical education with IUPAC standards and quantum charge analysis and could enhance students’ conceptual understanding of coordination bonding.
Nguyen et al. (Thu,) studied this question.