Thallium

Thallium (Tl) is a chemical element or a metal of the main Group 13 (IIIa, or boron group) of the periodic table. It is poisonous. Like lead, thallium is also a soft and low-melting element. Freshly cut thallium has a metallic lustre that dulls to bluish-grey upon exposure to air.

Hydrogen

Identity.

Thallium is a chemical element with the symbol Tl and the atomic number 81. It is a soft, gray, post-transition metal that is not found free in nature. It has a metallic luster that quickly tarnishes when exposed to air. Thallium has two stable isotopes: thallium-203 and thallium-205.

History.

Tin is a metal that typically occurs in nature in the form of the mineral cassiterite. It is believed that tin was discovered about 6-6.5 thousand years ago, around the same time as copper1. Tin was widely known in the Mediterranean countries, Persia, and India. Egyptians imported tin from Persia for the production of bronze1. Tin is primarily obtained from the mineral cassiterite and is chiefly mined in Malaysia2.

Usage.

Thallium is a relatively rare, soft, silvery-white metal with the chemical symbol Tl and atomic number 81. It is the heaviest stable member of the group 13 elements. Despite its rarity, thallium has found several uses in various fields.

  • Electronics: Thallium's low melting point and high electrical conductivity make it useful in the production of specialized electronic components, such as photocells, photoresistors, and infrared detectors.
  • Medical Imaging: Thallium-201, a radioactive isotope of thallium, is used in nuclear medicine for diagnostic imaging, particularly in cardiac stress tests. It helps assess blood flow to the heart muscle and identify areas of reduced blood supply.
  • Pharmaceuticals: Thallium compounds have been historically used in some medications, primarily as depilatories (hair removal agents) and rodenticides (rat poisons). However, due to their high toxicity, these applications have been largely discontinued.
  • Scientific Research: Thallium's unique properties have made it a subject of interest in scientific research. It is used in various studies related to material science, spectroscopy, and nuclear physics.

Sources.

Trace amounts found in copper, lead, zinc, and other sulfide ores. These are the major source of commercial thallium. Food contaminated with thallium, especially vegetables, fruit, and grains that accumulate thallium from soil. Workplace air in industries that use thallium, such as electronics, glass, and pharmaceuticals. Cigarette smoke, which contains thallium from tobacco plants. Hazardous waste sites, soil, air, and water that contain thallium from industrial or agricultural activities.