ChemGlobe

Thallium

Metalsolid
Symbol: Tl
Atomic number: 81
Atomic mass: 204.3833
Group: Metal
CAS-number: 7440-28-0

Deutsch
Français
Español
Physical data
Isotopes
Other info
Navigation
In
Indium
Hg Mercury To Periodic Table LeadPb
Ununtrium
Uut

Go to element

Physical data

Electronic dataThermal dataSteric data
Shells: 2, 8, 18, 32, 18, 3
Orbitals: [Xe] 4f14 5d10 6s2 6p1
Electronegativity: 1.8, 1.4
1. Ionization potential: 6.1083 eV
2. Ionization potential: 20.428 eV
3. Ionization potential: 29.829 eV
Oxidation states: 3, 1
Electrical conductivity: 0.0617 10^6
Melting point: 303.5 °C
Boiling point: 1457 °C ±10
Specific heat: 0.13 J/gK
Heat of fusion: 4.142 kJ/mol
Heat of vaporization: 164.10 kJ/mol
Thermal conductivity: 0.461 W/cmK
Atomic radius: 2.08 Å
Ionic radius: 1.59 Å (+1)
Covalent radius: 1.48 Å
Atomic volume: 17.2 cm³/mol
Density (293 K): 11.85 g/cm³
Crystal structure: hexagonal
hexagonal

Isotopes

NuclideAbundance [%]MassSpinHalflifeDecay modeDecay tree
200Tl 0 200 2 1.087d EC, β+ View
201Tl 0 201 1/2 3.038d EC View
202Tl 0 202 2 12.23d EC, β+ View
203Tl 29.52 202.972 1/2 -- --
204Tl 0 204 2 3.78y β-, EC View
205Tl 70.48 204.974 1/2 -- --
206Tl 0 206 0 4.20m β- View
207Tl 0 207 0 4.77m β- View
208Tl 0 208 0 3.053m β- View
209Tl 0 209 1/2 2.20m β- View
210Tl 0 210 0 1.30m β- View

Other info

Name origin:Greek: thallos (green twig), for a bright green line in its spectrum.
Description:Soft gray metal that looks like lead.
Discovered by:Sir William Crookes
Year:1861
Place:England
Sources:Found in iron pyrites. Also in crookesite, hutchinsonite and lorandite. Most is recovered from the byproducts of lead and zinc refining.
Use(s):Its compounds are used in rat and ant poisons. Also for detecting infrared radiation.