Thallium is a soft gray metal that is never found in its free form in nature. It is a chemical element with the atomic number 81 and it is represented by the symbol Tl. Thallium is relatively common in the crust of the Earth commonly associated with minerals that contain potassium. However, the metal is not produced from the sources because it is not economical. Instead, commercial important thallium comes as a trace element in the mining of copper, zinc, lead and other heavy metal ores. Although it is extremely toxic to many organisms, including humans, thallium has many important uses. Let’s find out who discovered this element.
Who discovered thallium?
Interestingly, thallium was discovered by two separate chemists at almost the same time. In 1861 British chemist William Crookes and French chemist Claude Auguste Lamy both independently discovered the new element via flame spectroscopy. Using this method, they both noticed the bright green emission lines that indicated the presence of a new element in their mineral samples. This also led to the name for the element, which comes from the Greek word thallos and means “green shoot or twig”. In 1862 Crookes isolated a very small amount of the metal for the first time and later Lamy was able to produce the a larger amount of the pure metal. In the same year controversy about who discovered the element surfaced as Lamy was awarded a medal for his discovery. Crookes protested and was also awarded the same prize. The situation intensified from there, but eventually Crookes was elected to the member of the Royal Society in 1863 and the debate virtually ended. Today, both chemists are credited with the discovery.
Did you know?
Thallium was once the poison of choice for killing rats. However, because it is tasteless it led to a number of accidental poisonings and was also used as a poison for murder. It is now banned in most countries!