Ethidium bromide

Ethidium bromide is a fluorescent compound commonly used as a nucleic acid stain. It is a strong mutagen as well, and may possibly be a carcinogen or teratogen. Ethidium bromide is excited by UV light and emits in the red-orange region. It is also known as 2,7-Diamino-10-ethyl-9-phenyl-phenanthridinium bromide. As with most fluorescent compounds, it is aromatic. The main portion of the molecule is a tricyclic structure with aniline (amino-benzene) groups on either side of a pyridine (six-atom, nitrogen-containing, aromatic ring).