Thallium (Tl)
"The Poisoner's Poison, a sinister villain who is tasteless, odorless, and mimics other illnesses."
A memorable persona to anchor Tl in your mind.
11.85
Grams per cm³
304
Celsius (°C)
196
Radius (pm)
Daily Life Link
Thallium is found as a component of some low-temperature thermometers.
Discovery & History
Year Discovered
1861
Discovered By
William Crookes
Origin of Name
"Thallium is derived from the Greek ''thallos'', meaning a green twig."
Technical Properties
Atomic Mass
204.38 u
Standard State
solid
Boiling Point
1473°C
Electron Configuration
[Xe] 4f145d106s26p1
1st Ionization Energy
6.108 eV
Electron Affinity
N/A
Oxidation States
"Thallium is a soft, gray, malleable metal."
Did You Know?
It has been called the "poisoner's poison" because it is colorless, odorless, and tasteless, and its slow-acting symptoms are difficult to distinguish from other illnesses.
One of the classic signs of thallium poisoning is the loss of hair.
It was discovered spectroscopically by its brilliant green spectral line, and its name comes from the Greek 'thallos', meaning 'green twig'.
Despite its toxicity, it has been used in some specialty electronics and low-temperature thermometers.