Thallium

Thallium
Properties
Atomic symbol	Tl
Atomic number	81
Classification	Metals
Atomic mass	204.3833 amu
Other Information
Date of discovery	1861
Name of discoverer	Sir William Crookes
Name origin	From the Greek thallos, meaning a young shoot or green twig, due to the bright green line in its spectrum.
Uses	Originally, its compounds were used in rat and ant poisons, but has been prohibited since 1975 in many countries. Also used for detecting infrared radiation and in heart muscle research.
Obtained from	It is generally obtained as the by-product of zinc and lead smelting. Also found in iron pyrites, crookesite, hutchinsonite and lorandite.

Thallium is a soft poisonous metallic element. Its physical properties are similar to those of lead.