An easy way to identify organic compounds is to look for several atoms in a long chain. These long chains are covalent bonds. So, the length of the bond and the factors affecting it becomes very important.
Such a bond formation occurs only when the atoms that want to form covalent bonds have the right concentration, orientation, and speed.
Meeting these criteria is necessary for the interested atoms so that they possess the minimum required energy needed to overcome the interatomic electron repulsions and come closer. And once closer, the combining atoms will be attracted due to their opposite electrostatic nature- the negative electron of one atom with the positive nuclei of the other.
Once all these parameters are in order, the atoms then reach a favorable distance. At this length, atoms’ attractive and repulsive forces are balanced, their orbitals embrace or overlap, and they are ready to form a covalent bond.
This distance between them is very crucial. If the atoms come any closer, the repulsive forces between the nuclei and electrons push them away. If the atoms go a little farther away, the force of attraction between the nuclei of one atom and the electrons of the other increases.
The equilibrium distance where there is a delicate balance between the two opposing forces is called the bond length.
Another way to define it is by using the atomic radius. As two atoms combine to form a bond, then the radius is one-half of the covalent bond, so the sum of the two covalent radii equals the covalent bond length between two atoms.
Bond lengths are commonly measured in picometres (pm), and the measurements are done using X-ray diffraction or electron diffraction spectroscopy methods.
Various factors affect the bond length. They are - the number of bonds, size of the atoms, electronegativity of the atoms, and s-character.
For detailed explanation on the factors affecting the bond length, subscribe below.