The inorganic compound tellurium tetrachloride formula TeCl4 is the crystalline salt of tellurium in its +4 oxidation state. The chemical decomposes in water to produce tellurium dioxide and hydrochloric acid. It is toxic and corrosive to the skin and eyes, and can cause respiratory irritation. It is also a possible carcinogen.
It is readily soluble in acetone, methyl sulfoxide, dimethylformamide, and hexane. It is also slightly soluble in ethyl alcohol and benzene. Tellurium tetrachloride is insoluble in cyclohexane, hexanes, chloroform, and carbon tetrafluoride. Tellurium tetrachloride reacts with acetic acid to form the corresponding trans-2-halocyclohexyl tellurium trihalide. The salt also reacts with electron-rich arenes to give aryl tellurium compounds, such as diaryl telluride from anisole.
Unlike many other metal chlorides, TeCl4 is not readily soluble in water and does not react with it to form chloride salts or hydrochloric acid. The compound is a strong electrolyte and can conduct electricity when fused with another metal. It is also a weak reducing agent, forming soluble complexes with cyanide ions and nitric acid.
Tellurium is a rare earth element that is found naturally in low concentrations in many minerals, especially pyrite and sulfides. It is also found in ores, notably bismuth and selenium. In addition to being a common raw material for electronics, tellurium is used in photoreceptors, optical fibers, and batteries. It is also recovered from old selenium-tellurium photoreceptors, but there is little or no old scrap from which to extract secondary tellurium, and the global EOL recycling rate is very small (