by • 22/08/2013 • GeneralComments (0)383


The NH3 structure shows that central atom, Nitrogen, is surrounded by tour electron pairs.



In terms of EPRT, the tetrahedral is the only shape that gives the maximum repulsion.

But in NH3, N has a lone pair of electrons which repels the other bonding orbitals, due to which bond angle is reduced from 109.5º to 107 º.



In terms of HOM, Nitrogen utilizes only three of the four sp3 hybrid orbitals to form s- sp3 hybrid sigma bonds with three hydrogen atoms and having a non-bonding orbital on the Nitrogen atom.

N (ground state) : 1S² , 2S², 2px² , 2py1

N (excited state) : 1S² , 2S²  , 2px1 , 2py1 , 2py1


After hybridization four sp3 hybrid orbitals are formed

The electrons in the non-bonding orbital are associated with only one molecule, while other bonding orbitals are held together tightly by two nuclei of N and l-i»atoms, Due to this reason, the non-bonding orbital occupies a large volume and compresses the bonding orbitals reducing the bond angle from 109.5 º to 107 º.

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