Nitroso refers to a functional group in organic chemistry which has the NO group attached to an organic moiety. As such, various nitroso groups can be categorized as C-nitroso compounds (e.g., nitrosoalkanes; R-N=O), S-nitroso compounds (nitrosothiols; RS-N=O), N-nitroso compounds (e.g., nitrosamines, R1N(-R2)-N=O), and O-nitroso compounds (alkyl ... Found on http://en.wikipedia.org/wiki/Nitroso