Uses of Thallium 

    Thallium is odorless and tasteless which allows it to not be known of its presence, therefore Thallium sulfate was often used as a rodent and ant killer. Thallium sulfate worked well with rodents and mice because it was easily passed through their skin. Once the chemical was inside their bodies, it caused death. It is also useful in insecticides because it is very poisonous and dangerous. Since the Thallium sulfate had the same effect on humans, it was banned as a rodenticide in the United States because it would accidentally kill small children. Thallium bromide-iodide crystals are often used as infrared detectors. Mixing Thallium with Thallium bromide and Thallium iodide can produce glass for special infrared lenses. When Thallium is used with sulfur, selenium, and arsenic, it can make low melting glasses. Thallium was also originally used to treat ringworm and other infectious skin diseases, but was banned when Thallium was found to be toxic. Thallium sulfide is sometimes used in photocells because Thallium sulfide can conduct light very well in certain kinds of light. Thallium and Mercury can be mixed together to make an alloy to make low-temperature thermometers, relays, and switches, which will remain a liquid at –60ºC or -76ºF. Thallium-activated iodide crystals are used in portable devices to detect gamma radiation. Since Thallium gives off a bright green light, it is also used in rockets and flare.