Main Page | See live article | Alphabetical index In chemistry, a hydrazone is a compound with the structure R2C=NNR2, differing from a ketone or aldehyde by the replacement of the double bonded oxygen with the =NNR2 functional group. They are formed usually by the action of hydrazine on ketones or aldehydes. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.