I Debye =10−18 esu-cm =3.335×1030C−m (coulomb metre). A dipole moment arises in any system in which there is a separation of charge. They can, therefore, arise in ionic bonds as well as in covalent bonds. Dipole moments occur due to the difference in electronegativity between two chemically bonded atoms. Mathematically Dipole moment (µ)= charge (Q)× distance of separation (r) It is measured in Debye units denoted by ' D '. 1D=3.33564×10−30C−m, where C is coulomb and m denotes metre. Proof 1 Debye =10−10 esu ×10−8C−m =10−18 esu C-m =10−18esuC−m×3.335×10−10C∕esu×10−2m∕C−m =3335×10−30C−m.