Thallides are compounds containing anions composed of thallium. Thallium may occur as a monatomic ion (Tl5− in LiMg2Tl), as a cluster of several atoms (e.g. Tl48−), or as a polyatomic structure Tlnn− in thallides. They are a subclass of trielides, which also includes gallides and indides. A more general classification is polar intermetallics, as clusters contain delocalized multicentre bonds. Thallides were discovered by Eduard Zintl in 1932.
Mixed anion compounds with thallides include halides (bromides and chlorides), oxides, and tetrelates (silicate, germanate).