carbazide

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| image1 = Carbohydrazide.png

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| caption1 = Carbohydrazide, the simplest carbazide

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In chemistry, a carbazide is a functional group with the general formula {{chem2|RNH\sNH(C\dO)NH\sNHR}}. They can be derived from the condensation of carbonic acid with a hydrazine. Carbohydrazide is the simplest carbazide, with another common carbazide being diphenylcarbazide, which is used as an analytical reagent.{{cite journal|doi=10.1039/AN9366100164|title=Diphenylcarbazide. An internal indicator for use in the titration of iron with dichromate|year=1936|last1=Crossley|first1=H. E.|journal=The Analyst|volume=61|issue=720|pages=164|bibcode = 1936Ana....61..164C }}

Diphenylcarbazide forms an intense blue color with chromium in the hexavalent state. It has an absorptivity coefficient of about 3400. That means very small amounts of chromium can be detected; 25 micrograms in 25 mL of solution are too dark to read on a spectral device, so concentrations well below that can be detected.