The nature of halogen...halogen interactions: a model derived from experimental charge-density analysis

Area of Science:

• * Physical Chemistry
• * Quantum Chemistry
• * Crystallography

Background:

• * Understanding intermolecular forces is crucial in chemistry.
• * The nature of halogen bonding, particularly chlorine-chlorine interactions, requires further elucidation.
• * Hexachlorobenzene (C(6)Cl(6)) serves as a model system for studying such interactions.

Purpose of the Study:

• * To experimentally demonstrate the attractive and anisotropic nature of the Cl-Cl interaction in C(6)Cl(6).
• * To provide a detailed model explaining the mechanism of this interaction at the atomic level.

Main Methods:

• * Analysis of electron density (rho(r)) expansion around chlorine nuclei.
• * Utilizing experimental data to support theoretical models of chemical bonding.

Main Results:

• * Experimental evidence confirms a slightly attractive and anisotropic Cl-Cl interaction in C(6)Cl(6).
• * The interaction is characterized by the interplay between electron-deficient and electron-rich regions on adjacent chlorine atoms.

Conclusions:

• * The Cl-Cl interaction in C(6)Cl(6) is a form of bonding attraction.
• * This interaction is driven by electrostatic complementarity between polarized chlorine atoms.