• Skip to page content
• Skip to site menu on this page

Periodic Table of Elements

Element Thallium - Tl

Comprehensive data on the chemical element Thallium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Thallium. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies.

Thallium Menu

• Thallium Page One
  • Overview of Thallium
  • Thallium's Name in Other Languages
  • Atomic Structure of Thallium
  • Chemical Properties of Thallium
  • Physical Properties of Thallium
  • Regulatory / Health
  • Who/When/Where/How
• Thallium Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides

Overview of Thallium

• Atomic Number: 81
• Group: 13
• Period: 6
• Series: Metals

Thallium's Name in Other Languages

• Latin: Thallium
• Czech: Thallium
• Croatian: Talij
• French: Thallium
• German: Thallium - s
• Italian: Tallio
• Norwegian: Thallium
• Portuguese: Tálio
• Russian: Таллий
• Spanish: Talio
• Swedish: Tallium

Atomic Structure of Thallium

• Atomic Radius: 2.08Å
• Atomic Volume: 17.2cm³/mol
• Covalent Radius: 1.48Å
• Cross Section (Thermal Neutron Capture) σ_a/barns: 3.43
• Crystal Structure: Hexagonal

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d¹⁰f¹⁴ 5s²p⁶d¹⁰ 6s²p¹

• Electrons per Energy Level: 2,8,18,32,18,3

  Shell Model
  

• Ionic Radius: 1.5Å
• Filling Orbital: 6p¹
• Number of Electrons (with no charge): 81
• Number of Neutrons (most common/stable nuclide): 123
• Number of Protons: 81
• Oxidation States: 3,1
• Valence Electrons: 6s²p¹

  Electron Dot Model
  

Chemical Properties of Thallium

• Electrochemical Equivalent: 7.625g/amp-hr
• Electron Work Function: 3.84eV
• Electronegativity: 2.04 (Pauling); 1.44 (Allrod Rochow)
• Heat of Fusion: 4.142kJ/mol
• Incompatibilities:

• Ionization Potential
  • First: 6.108
  • Second: 20.428
  • Third: 29.829
• Valence Electron Potential (-eV): 9.6

Physical Properties of Thallium

• Atomic Mass Average: 204.3833
• Boiling Point: 1746K 1473°C 2683°F
• Coefficient of lineal thermal expansion/K^-1: 28E^-6
• Conductivity

  Electrical: 0.0617 10⁶/cm Ω
  Thermal: 0.461 W/cmK

• Density: 11.85g/cc @ 300K
• Description:

  Silvery white metal that readily tarnishes in moist air and reacts with steam to form TlOH.

• Elastic Modulus:
  • Bulk: 28.5/GPa
  • Rigidity: 2.71/GPa
  • Youngs: 7.9/GPa
• Enthalpy of Atomization: 179.9 kJ/mole @ 25°C
• Enthalpy of Fusion: 4.27 kJ/mole
• Enthalpy of Vaporization: 162.1 kJ/mole
• Flammablity Class:
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 26.4 MN m^-2
  • Mohs: 1.2
• Heat of Vaporization: 164.1kJ/mol
• Melting Point: 577K 304°C 579°F
• Molar Volume: 17.25 cm³/mole
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.13J/gK
• Vapor Pressure = 5.33E-06Pa@304°C

Regulatory / Health

• CAS Number
  • 7440-28-0
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: 0.00048
  • Bone/p.p.m: 0.002
  • Liver/p.p.m: 0.004-0.033
  • Muscle/p.p.m: 0.07
  • Daily Dietary Intake: 0.0015 mg
  • Total Mass In Avg. 70kg human: 0.5 mg
• Discovery Year: 1861
• Name Origin:

  Greek: thallos (young shoot/green twig) from a bright-green line in its spectrum.

• Abundance of Thallium:
  • Earth's Crust/p.p.m.: 0.6
  • Seawater/p.p.m.: 0.000014
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 8
• Sources of Thallium:

  Found in iron pyrites, crookesite, hutchinsonite and lorandite. It is generally obtained as the by-product of zinc and lead smelting. Annual world wide production is around 30 tons.

• Uses of Thallium:

  Its compounds are used in rat and ant poisons. Also for detecting infrared radiation and heart muscle research.

• Additional Notes:

  While thallium was discovered by William Crookes in 1861, it was firs isolated by C.A. Lamy in 1862 in Paris France

Thallium Menu

• Thallium Page One
  • Overview of Thallium
  • Thallium's Name in Other Languages
  • Atomic Structure of Thallium
  • Chemical Properties of Thallium
  • Physical Properties of Thallium
  • Regulatory / Health
  • Who/When/Where/How
• Thallium Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides

References

A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page.

Related Resources

• Anatomy of the Atom
  Answers many questions regarding the structure of atoms.
• Molarity, Molality and Normality
  Introduces stoichiometry and explains the differences between molarity, molality and normality.
• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

If you need to cite this page, you can copy this text:

Kenneth Barbalace. Periodic Table of Elements - Thallium - Tl. EnvironmentalChemistry.com. 1995 - 2024. Accessed on-line: 12/21/2024
https://EnvironmentalChemistry.com/yogi/periodic/Tl.html
.