Information-Theoretic Perspectives on Chemical Problems: Recent Developments and Applications

Information-theoretic approach (ITA) has emerged as a powerful density-based framework for interpreting molecular structure, stability, and reactivity within density functional theory (DFT). By treating the electron density as a probability distribution, information-theoretic (IT) descriptors provide physically transparent measures of electron delocalization, localization, and density reorganization, offering an alternative to traditional orbital-based interpretations. This review presents a focused account of the theoretical foundations and chemical significance of IT descriptors and highlights their growing role in density-based chemical analysis. Selected applications are discussed to illustrate how these measures successfully rationalize molecular stability, bonding patterns, reactivity trends, and structure-property relationships across diverse chemical systems. The interplay between IT descriptors and conceptual DFT quantities is also examined, emphasizing their complementary nature in chemical reactivity studies. Overall, this review underscores the versatility and predictive capability of information-theoretic functionals of the electron density and their potential to advance a unified, orbital-free framework for understanding chemical behavior.