What is the difference between the structure of nitrito-o and nitrito-n?
The last letter of nitrite-o and nitrite-n depicts the atom which is attached to the other atom. This phenomenon is called linkage isomerism and is an important concept in both organic and inorganic chemistry.


inorganic chemistry




This complex exhibits linkage isomerism which results in two possible ways of attachment of ligand to the central atom. First one, the $\ce{NO2}$ ligates with the central atom through the nitrogen atom and thus is called pentaammine nitrito-N-cobalt (III) chloride and the second one,  $\ce{NO2}$ ligates with the central atom through the oxygen atom and thus is called pentaammine nitrito-O-cobalt (III) chloride. In this case, $\ce{NO2}$ is called ambident ligant and is represented as nitrito-κ-N and nitrito-κ-O, replacing the old system of trivial names such as nitro and nitroso.


organic chemistry


Alkyl nitrite forms two isomers:- $\ce{RNO2}$ (called alkyl nitrite-N) and $\ce{R-O-N=O}$ (called alkyl nitrite-O). [For preparation of these two isomers, see this answer].