How does Sp3 hybridization work for Nitrogen in #NH_2^-# ?

2 Answers
Mar 3, 2016

There are formally 4 electron pairs distributed around the nitrogen in the amide molecule; #sp^3# hybridization would be the description.

Explanation:

Of course, there are likewise 4 electron pairs distributed around the nitrogen centre in ammonia, #:NH_3#. #sp^3# hybridization would be the description, and the gross structure (of electron pairs) is that of a tetrahedron. But we describe molecular geometry on the basis of actual atoms, so the structure of ammonia is pyramidal.

Likewise for #H_2N^-#, the amide ion, the 4 electron pairs are distributed around nitrogen as a tetrahedron. Again, we describe structure on the basis of #N-H# bonds only. The structure of the amide ion is thus akin to that of water, that is bent because there are also 2 lone pairs on the central oxygen/nitrogen atom.

Mar 3, 2016

Sp3 hybridization for Nitrogen in #NH_2^- # has tetrahedrical geometry

Explanation:

Nitrogen has 5 outer electrons, in #NH_2^- # it gains an extra electron. Of the 6 electrons, 2 are shared with 2 hydrogen atoms to form 2 sigma bonds, the remaining 4 eletrons fill 2 orbitals with 2 lonely electron pairs, similarly to #H_2O#.