Thallium, 81Tl
Thallium
Pronunciation/ˈθæliəm/ (THAL-ee-əm)
Appearancesilvery white
Standard atomic weight Ar°(Tl)
Thallium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
In

Tl

Nh
mercurythalliumlead
Atomic number (Z)81
Groupgroup 13 (boron group)
Periodperiod 6
Block  p-block
Electron configuration[Xe] 4f14 5d10 6s2 6p1
Electrons per shell2, 8, 18, 32, 18, 3
Physical properties
Phase at STPsolid
Melting point577 K ​(304 °C, ​579 °F)
Boiling point1746 K ​(1473 °C, ​2683 °F)
Density (at 20° C)11.873 g/cm3[3]
when liquid (at m.p.)11.22 g/cm3
Heat of fusion4.14 kJ/mol
Heat of vaporization165 kJ/mol
Molar heat capacity26.32 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 882 977 1097 1252 1461 1758
Atomic properties
Oxidation statescommon: +1, +3
−5,[4] −2,? −1,? +2?
ElectronegativityPauling scale: 1.62
Ionization energies
  • 1st: 589.4 kJ/mol
  • 2nd: 1971 kJ/mol
  • 3rd: 2878 kJ/mol
Atomic radiusempirical: 170 pm
Covalent radius145±7 pm
Van der Waals radius196 pm
Color lines in a spectral range
Spectral lines of thallium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp) (hP2)
Lattice constants
Hexagonal close packed crystal structure for thallium
a = 345.66 pm
c = 552.52 pm (at 20 °C)[3]
Thermal expansion29.9 µm/(m⋅K) (at 25 °C)
Thermal conductivity46.1 W/(m⋅K)
Electrical resistivity0.18 µΩ⋅m (at 20 °C)
Magnetic orderingdiamagnetic[5]
Molar magnetic susceptibility−50.9×10−6 cm3/mol (298 K)[6]
Young's modulus8 GPa
Shear modulus2.8 GPa
Bulk modulus43 GPa
Speed of sound thin rod818 m/s (at 20 °C)
Poisson ratio0.45
Mohs hardness1.2
Brinell hardness26.5–44.7 MPa
CAS Number7440-28-0
History
Namingafter Greek thallos, green shoot or twig
DiscoveryWilliam Crookes (1861)
First isolationClaude-Auguste Lamy (1862)
Isotopes of thallium
Main isotopes[7] Decay
abun­dance half-life (t1/2) mode pro­duct
201Tl synth 3.0421 d ε 201Hg
203Tl 29.5% stable
204Tl synth 3.78 y β 204Pb
ε + β+ 204Hg
205Tl 70.5% stable
 Category: Thallium
| references
Tl · Thallium
Hg ←

ibox Hg

iso
81
Tl  [e]
IB-Tl [e]
IBisos [e]
→ Pb

ibox Pb

indexes by PT (page)
child table, as reused in {IB-Tl}
Main isotopes of thallium
Main isotopes[7] Decay
abun­dance half-life (t1/2) mode pro­duct
201Tl synth 3.0421 d ε 201Hg
203Tl 29.5% stable
204Tl synth 3.78 y β 204Pb
ε + β+ 204Hg
205Tl 70.5% stable
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (46) · (this table: )

References

  1. ^ "Standard Atomic Weights: Thallium". CIAAW. 2009.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ a b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  4. ^ Dong, Z.-C.; Corbett, J. D. (1996). "Na23K9Tl15.3: An Unusual Zintl Compound Containing Apparent Tl57−, Tl48−, Tl37−, and Tl5− Anions". Inorganic Chemistry. 35 (11): 3107–12. doi:10.1021/ic960014z. PMID 11666505.
  5. ^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  6. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  7. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.