How many resonance structures does the nitrate ion, #NO_3^-1# have?

1 Answer
May 26, 2016

Answer:

#3# resonance isomers are possible, but this is a formalism.

Explanation:

Nitrate ion is a good example to practise on, because a single resonance resonance isomer depicts 3 of the four atoms in the negative ion with formal charges:

i.e. #""^+N(=O)(-O^-)_2#. The nitrogen centre is quaternized with a formal positive charge, and the formally singly bound oxygen each bear a formal negative charge. How are the 24 valence electrons distributed?