| Thallium is applied mostly as its compounds. Single crystals of solid halogenides such as TlBr - TlI and TlCl - TlBr are used in infrared optics, whereas TlCl and TlCl-TlBr are used in Cherenkov-light detector radiators. Tl2O has been used to manufacture glasses; thallium oxides, oxysulphides, tellurides and selenides are components of semiconductors used in photoresistors, rectifiers and vidicons. The water solution of thallium malonate formate (Clerici solution) is used for mineral separation. Thallium amalgam with freezing point at 59°C is utilized in low-temperature thermometers. Thallium metal alloys are used in bearing and low-melting-temperature alloys as well as in water oxygen measuring devices. 204Tl is used as beta-radiation source. |