Molecular packing refers to the arrangement of molecules in a solid material. It encompasses the study of how molecules pack together in crystals, polymers, and other solid-state materials. Understanding molecular packing is crucial in various fields such as material science, crystallography, and pharmaceuticals, as it influences the physical, chemical, and mechanical properties of materials. Researchers investigate factors such as intermolecular interactions, symmetry, and packing efficiency to determine how molecules are arranged in a solid and how these arrangements affect the overall properties of the material.