81Tl Thallium

Description

Named from the Greek word meaning “green twig” (a bright green line is present in the element’s spectrum), thallium is a very soft, bluish-white metal that can be cut with a knife. It easily reacts with air, water (especially steam) and most acids. Thallium resembles lead in appearance, but chemically resembles aluminum. Thallium is used in photocells, infrared detectors, solders, and glass that melts at low temperatures. When amalgamated with mercury, thallium depresses mercury’s freezing point by twenty degrees. It has been used as an insecticide and rodent poison, as well as in treating skin infections. These uses have been discontinued, due to thallium’s high toxicity. Biological Rating No known benefit for life processes in plants and animals. Biological Benefits Thallium has no known biological use.

Biological Benefits

Thallium has no known biological use.

Role in Life Processes

No known benefit for life processes in plants and animals.

Sources

Thallium is chiefly obtained as a by-product of zinc and lead processing. Thallium minerals are rare. It is often found in alkali metal minerals, especially those of potassium and cesium. Thallium-bearing minerals include crooksite, lorandite and thalcusite which occur as minute inclusions in sphalerite. Thallium is chiefly obtained as by-product of zinc and lead processing, and recovered from flue dusts in smelters. Thallium is mined in the USA. The manganese nodules on the ocean floor also contain substantial amounts of thallium.