NH2

from The Collaborative International Dictionary of English v.0.48

Amidogen \A*mid"o*gen\, n. [Amide + -gen.] (Chem.)
   A compound radical, {NH2}, not yet obtained in a separate
   state, which may be regarded as ammonia from the molecule of
   which one of its hydrogen atoms has been removed; -- called
   also the {amido group}, and in composition represented by the
   form amido.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Amido \A*mi"do\, a. [From {Amide}.] (Chem.)
   Containing, or derived from, amidogen.
   [1913 Webster]

   {Amido acid}, an acid in which a portion of the nonacid
      hydrogen has been replaced by the amido group. The amido
      acids are both basic and acid.

   {Amido group}, amidogen, {NH2}.
      [1913 Webster]

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