Dipole Moment.
H5N1 molecule containing a polar bond has a positive too a negative destination too is called a dipole. As in that location is a divergence inwards charge, separated yesteryear a distance, the molecule has an electrical moment, called the dipole moment. It is non possible to decide the dipole minute of an private bond inwards a molecule but the full minute of the molecule tin locomote determined, which is a vectorial amount of the private bond moments. The private bond moments are roughly the same from molecule to molecule. 
The dipole minute of a molecule measures the concentration of positive too negative charges inwards dissimilar parts of the molecule too is equal to, the production of the size of accuse too the distance betwixt the centres of the positive too the negative charges. It tin locomote measured if a gas whose molecules accept dipole minute is placed betwixt the plates of a condenser too a potential divergence is applied to the plates; the molecules tend to orient themselves alongside the electrical plain too alter the capacity of the condenser. The ratio of the capacity of a condenser inwards the presence of a heart too individual to the capacity inwards vacuum is the dielectric constant, of the substance. Since the alignment of the molecules is opposed yesteryear thermal agitation, it is possible to calculate the dipole minute of the molecule from the variation of dielectric constant alongside the temperature. The dipole moment is designated yesteryear the symbol μ . An electron has a accuse of 4.80 x 10-10 electrostatic units (esu) too the accuse at either destination of the bond is less than this but of the lodge of 10-10 esu. The distance betwixt the centres of the charges are of the lodge of 10-8 cm, therefore, the green magnitude of the dipole moment is of the lodge of 10-18- esu x cm. This quantity is known every bit a debye unit of measurement or but a debye. It is given the symbol D. Thus chlorine fluoride which has a dipole minute = 0.88 x 10-18 esu xcm is said to accept a dipole minute of 0.88 D.
Many organic molecules which accept polar bonds produce non possess molecular dipoles because the private bond moments are too so oriented that they cancel out ane another. For example μ = 0D for carbon dioxide because the molecule is linear too the 2 bond moments which are equal too inwards reverse administration cancel out each other. 
Similarly μ = 1D for cis -1,2- dichloro ethylene where the bond moments are oriented too so every bit to supply over all electrical dissymmetry. The trans isomer has μ = OD, since the 2 private bond moments are oriented too so every bit to cancel each other. 
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