Page 140 - The Periodic Table Book

81
Tl Thallium

State: Solid
81 81 123 Discovery: 1861

The Boron Group Thallium alum contains small amounts of thallium.
Forms
The grey crust on this aluminium mineral

This mineral contains
iron, sulfur, and tiny
amounts of thallium. Pyrite

This soft and silvery metal is kept
in a sealed glass tube as it is highly
toxic and reacts easily with air.
Laboratory sample of pure thallium in an airless vial

Thallium was named after the Greek both chemists worked separately, they found
word thallos, which means “green shoot”: the element in the same way – as a residue while
it was first identified from the colours in its making strong acids using the mineral pyrite.
flame, which includes a bright green light. Thallium was later found to exist in larger amounts
Thallium was discovered in 1861 by William in other minerals, including thallium alum.
138 Crookes and Claude-Auguste Lamy. Although Pure thallium is toxic and has to be handled

138-139_Thallium_Nihonium.indd 138 02/12/16 6:54 pm