• # question_answer 14) Define the bond length.

It is defined as the average distance between the centres of the nuclei of the two bonded atoms in a molecule. It is usually expressed in angstrom unit $(\overset{{}^\circ }{\mathop{\text{A}}}\,)$ or picometer (pm). It is measured by spectroscopic X-ray diffraction and electron diffraction techniques. The bond length in a covalent molecule AB is the sum of the covalent radius of the bonded atoms. Bond length = ${{r}_{A}}+{{r}_{B}}$ The factors such as resonance, electronegativity, hybridization, steric effects, etc., affect the bond length.