From Greek thallos, meanin a green shoot or twig
Thallium was discovered spectroscopically by Sir William Crookes in 1861, in London.
In 1862, Claude-Auguste Lamy used a spectrometer to determine the composition of a selenium-containing substance which was deposited during the production of sulfuric acid from pyrite.
He noticed the new green line in the spectra and concluded that a new element was present.
Agatha Christie made use of thallium's toxicity in her novel The Pale Horse
Abundance in Earth's crust
0.000053%
Abundance in Universe
5×10-8%
Thallium selenide has been used in a bolometer for infrared detection.
Thallium is also used in gamma radiation detection equipment.
Thallium oxide has been used to produce glasses with a high index of refraction, and is used in the manufacture of photo cells.
Some of the electrodes in dissolved oxygen analyzers contain thallium.
Thallium and its compounds are highly toxic
