diazonium salt

For a discussion of copiers using the diazo process, see Whiteprint. Diazo refers to a type of organic compound that has two linked nitrogen (azo) compounds. The general formula is R2C=N2. The simplest example of a diazo compound is diazomethane. The electronic structure of diazo compounds involves a positive charge on the central nitrogen and negative charge distributed between the terminal nitrogen and the carbon. Some of the most stable diazo compounds are α-diazoketones and α-diazoesters since the negative charge is delocalized into the carbonyl. In contrast, most alkyldiazo compounds are explosive.
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Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group with the characteristic structure of R-N2+ X- where R can be any organic residue such alkyl or aryl and X is an inorganic or organic anion such as a halogen. Historically, diazonium salts have been developed as important intermediates in the organic synthesis of dyes.
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A diazonium salt is a compound with general form Ar-N N+X-, where Ar represents a substituted benzene ring and X- is a halide ion such as chloride. Diazonium salts are unstable and explosive in dry form. They are used to manufacture many different organic compounds, including azo dyes . See also diazotization .