Chemical Bonding and the Role of Node-Induced Electron Confinement

The chemical bond is the cornerstone
of chemistry, providing
a
conceptual framework to understand and predict the behavior of molecules
in complex systems. However, the fundamental origin of chemical bonding
remains controversial and has been responsible for fierce debate over
the past century. Here, we present a unified theory of bonding, using
a separation of electron delocalization effects from orbital relaxation
to identify three mechanisms [node-induced confinement (typically
associated with Pauli repulsion, though more general), orbital contraction,
and polarization] that each modulate kinetic energy during bond formation.
Through analysis of a series of archetypal bonds, we show that an
exquisite balance of energy-lowering delocalizing and localizing effects
are dictated simply by atomic electron configurations, nodal structure,
and electronegativities. The utility of this unified bonding theory
is demonstrated by its application to explain observed trends in bond
strengths throughout the periodic table, including main group and
transition metal elements.

化学键（chemical bond）是化学学科的基石，为理解和预测复杂体系中分子的行为提供了概念性框架。然而，成键作用（chemical bonding）的本质起源至今仍存在争议，在过去一个世纪间引发了激烈的学术争论。本研究提出了统一成键理论，通过将电子离域（electron delocalization）效应与轨道弛豫（orbital relaxation）效应相分离，确立了三类在成键过程中调控动能（kinetic energy）的机制：节点诱导限域（node-induced confinement，通常与泡利排斥（Pauli repulsion）相关，但其适用范围更广）、轨道收缩（orbital contraction）与极化（polarization）。通过对一系列典型化学键的分析，本研究表明，降能离域与定域效应之间的精妙平衡，仅由原子电子组态（atomic electron configuration）、节点结构（nodal structure）及电负性（electronegativity）所决定。该统一成键理论的实用性，通过其应用于解释元素周期表（涵盖主族元素（main group elements）与过渡金属元素（transition metal elements））中各类化学键强度的观测趋势得到了验证。