Thallium

Symbol: Tl
Atomic number: 81
Category: poor metals
Group: 13
Period: 6
Block: p
Atomic weight: 204.3833 g/mol
Electrons per shell: 2, 8, 18, 32, 18, 3
CAS number: 7440-28-0
Phase: solid
Density: 11.85 kg/dm³ (near room temperature)
Melting point: 577 K (304 °C, 579 °F)
Boiling point: 1746 K (1473 °C, 2683 °F)
Crystal structure: hexagonal
Oxidation states: 3, 1
Electronegativity: 1.62 (Pauling scale)
Name's origin: thallos
Name's meaning: a Greek word meaning 'a green shoot' - comes from thallium's bright green spectral emission lines
Facts:
- a soft gray malleable poor metal which resembles tin but discolors when exposed to air
- approximately 60-70% of thallium production is used in the electronics industry, and the rest is used in the pharmaceutical industry and in glass manufacturing
- is highly toxic and is used in rat poisons and insecticides, but its use has been cut back or eliminated in many countries
- because of its use for murder, thallium has gained the nicknames 'The Poisoner's Poison' and 'Inheritance Powder' (alongside arsenic)
- thallium metal is obtained as a by-product in the production of sulfuric acid by roasting of pyrite, and also in the smelting of lead and zinc ores