Thallium

Thallium

Hutchinsonite, a thallium-containing mineral

Thallium is a chemical element with the symbol Tl and atomic number 81. It is a soft, malleable metal that can be cut with a knife. Thallium is found in trace amounts in the Earth's crust and is primarily obtained as a byproduct of refining heavy metal sulfide ores.

Properties

Thallium is a post-transition metal that is not found free in nature. It is a member of the boron group and shares some properties with the other elements in this group, such as aluminium and gallium. Thallium is highly toxic and must be handled with care.

Physical Properties

Thallium is a soft, gray post-transition metal that resembles lead in appearance. It is highly malleable and can be easily cut with a knife. Thallium has a melting point of 304 °C and a boiling point of 1,473 °C.

Corroded thallium rod

Chemical Properties

Thallium is highly reactive and forms a variety of compounds. It readily oxidizes in air to form a dull gray oxide layer. Thallium compounds are often used in the electronics industry and in the production of special glasses.

Occurrence

Thallium is not found in its free form in nature. It is typically found in trace amounts in sulfide ores of heavy metals such as copper, lead, and zinc. Thallium is also found in some minerals, such as hutchinsonite, which contains thallium, lead, and arsenic.

Uses

Thallium has several applications, although its use is limited due to its toxicity. It is used in the electronics industry for the production of semiconductors and in the manufacture of special glass with a high refractive index. Thallium is also used in some medical imaging processes.

Toxicity

Thallium is highly toxic and can cause serious health effects if ingested or inhaled. It interferes with the function of several enzymes and can cause damage to the nervous system, liver, and kidneys. Thallium poisoning can occur through exposure to thallium compounds or through environmental contamination.

Related pages

• Lead
• Boron group
• Sulfide mineral