Thallium(I) carbonate
（重定向自Thallous carbonate）
Thallium(I) carbonate (Tl2CO3) is a chemical compound. It can be used for the manufacture of imitation diamonds, in chemical analysis to test for carbon disulfide, and as a fungicide. Like other thallium compounds, it is considered extremely toxic, with an oral median lethal dose of 21 mg/kg in mice. Due to its toxicity, it is listed in the United States List of Extremely Hazardous Substances as of 2007.