The radial distribution function (RDF), a fundamental statistical mechanic’s concept, characterizes the spatial arrangement of particles in a system. It describes the probability of finding a particle at a specific distance from a reference particle, providing important insights into the structure of liquids, ordered crystals, and disordered materials. RDFs are key tools for understanding molecular arrangements and are particularly valuable in studying the nature of fluids and fluid mixtures. This article reviews the RDF, focusing on its mathematical formulation, key features, and methods of determination, including X-ray and neutron scattering, integral equations, and molecular dynamics simulations. The relationship between RDFs and thermodynamic properties, including internal energy, chemical potential, and surface tension was elucidated. Also, RDFs contribute a key role in understanding intermolecular forces and hydrogen-bonded systems.

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