Polybrominated diphenyl ethers (PBDEs), are organobromine compounds that are used as flame retardant. Like other brominated flame retardants, PBDEs have been used in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics, polyurethane foams, and textiles.

The family of PBDEs consists of 209 possible substances, which are called congeners [PBDE = C12H(10?x)BrxO (x = 1, 2, ..., 10 = m + n)]. The number of isomers are 3 mono-, 12 di-, 24 tri-, 42 tetra-, 46 penta-, 42 hexa-, 24 hepta-, 12 octa-, 3 nona-, and 1 decabromodiphenyl esters, respectively. In the United States, PBDEs are marketed with trade names: DE-60F, DE-61, DE-62, and DE-71 applied to pentaBDE mixtures; DE-79 applied to octaBDE mixtures; DE 83R and Saytex 102E applied to decaBDE mixtures. The available commercial PBDE products are not single compounds or even single congeners but rather a mixture of congeners.

(Reference Sources: https://en.wikipedia.org)