ABSTRACT
We know that between two identical molecules, there exists a force of attraction, electrostatic in nature and inversely proportional to the distance between the two molecules, known as van der Waals force. This force is defined as a function of the energy required to bring the two molecules to a position where they are separated by a distance of R. R is defined as the distance at which the molecules cannot further approach each other, and knowing this distance makes it possible to draw a rigid model of the molecule. The molecule is thus confined by a surface formed by the envelopes of the spheres centered at each atom and which have a radius known as van der Waals radius. Usually, the molecule is represented by placing the atoms at the distance established for the covalent bonds, and then adding the van der Waals spheres. The resulting envelope represents the exterior shape of the molecule (Figure 2.2).
