Although chlorine compounds are the majority of the discovered compounds, bromides, iodides and fluorides have also been found. The tyrian purple, which is a dibromoindigo, is representative of the bromides, while the thyroxine secreted from the thyroid gland, is an iodide, and the highly toxic fluoroacetate is one of the rare organofluorides. These three representatives, thyroxine from humans, tyrian purple from snails and fluoroacetate from plants, also show that unrelated species use halocarbons for several purposes.[3][4][5]