Thallium (pronounce /ˈθæliəm/) is a chemical element with the symbol Tl and atomic number 81. This soft gray malleable poor metal resembles tin but discolors when exposed to air. Approximately 60-70% of thallium production is used in the electronics industry, and the rest is used in the pharmaceutical industry and in glass manufacturing. It is also used in infrared detectors. Thallium is highly toxic and is used in rat poisons and insecticides, and its use has been cut back or eliminated in many countries. It is used in murders and has the nicknames "The Poisoner's Poison" and "Inheritance powder" (alongside arsenic).