*SMILE*

SMILE

         The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings

          SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules 

          SMILE Fragments

Nitrite	ON(=O)
Nitro	N(=O)(=O)
Nitrate	ON(=O)(=O)