What is "carbazide"

In chemistry, a carbazide is a functional group with the general formula RNH-NH(C=O)NH-NHR. 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. The sulfur analog is called a thiocarbazide, of which thiocarbohydrazide is the simplest example.