Biuret is a chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the chemical formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 H₂NC(O)NHC(O)NH₂. It is the result of condensation of two molecules of urea

Urea

Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 and is a problematic impurity in urea-based fertilizers. This white solid is soluble in hot water.

The term "biuret" also describes a family of organic compounds with the functional group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...

 -(HN-CO-)₂N-. Thus dimethyl biuret is CH₃HN-CO-NR'-CO-NHCH₃.