Titanium tetrachloride, or TiCl4, is a chemical compound made up of one titanium atom and four chlorine atoms. It is a colorless liquid at room temperature and has a strong, pungent odor. TiCl4 is highly reactive and can easily hydrolyze in the presence of water, producing hydrochloric acid and titanium dioxide. TiCl4 is primarily used in the production of titanium metal and as a catalyst in various chemical reactions. It plays a significant role in the Kroll process, which is a method for extracting titanium from its ores. Due to its reactivity, proper safety precautions are necessary when handling TiCl4.