van der Waals radius

The van der Waals radius is a measure of the size of an atom when it is not bonded to other atoms, reflecting how close other atoms can come without overlapping. Imagine atoms as tiny spheres; this radius indicates the distance from the atom's center to the outermost point where another atom's electron cloud can approach without creating a strong bond. It helps us understand how atoms pack together in molecules and solids, influencing properties like boiling points and how substances interact. Essentially, it is a way to describe the "personal space" of an atom in molecular terms.