Home > Product list > TI


Thallium, including Technical Data, Safety Data and its high purity propertiesresearch, applications and other useful facts are discussed below. Scientific facts such as the atomic structure,ionization energyabundance on Earthconductivity and thermal properties are included. 

Thallium is primarily used for its electrical conductivity as thallium sulfide which changes with exposure to infrared light. This ability makes the compound useful in photocells. Thallium bromide-iodide crystals have been used as infrared optical materials. Thallium has been used, with sulfur or selenium and arsenic, to produce low melting glasses which becomes fluid between 125 and 150 C. These glasses have properties at room temperatures similar to ordinary glasses and are said to be durable and insoluble in water. Thallium oxide has been used to produce glasses with a high index of refraction, and is also used in the manufacture of photo cells. Thallium is available asmetal and compounds with purities from 99% to 99.9999% (ACS grade to ultra-high purity); metals in the form of foil, sputtering target, and rod, and compounds as submicron and nanopowder

Thallium facts, including appearance, CAS #, and molecular formula and safety data, research and properties are available for many specific states, forms and shapes on the product pages listed to the left. Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes.Nanoparticles and nanopowdersprovide ultra high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. 

Oxides are available in forms including powders and dense pellets for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Thallium is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries. 

Thallium is a Block P, Group 13, Period 6 element. The number of electrons in each of Thallium‘s shells is 2, 8, 18, 32, 18, 3 and its electronic configuration is [Xe] 4f145d10 6s2 6p1. In its elemental form thallium‘s CAS number is 7440-28-0. The thallium atom has a radius of and it‘s Van der Waals radius is Thallium and its compounds are highly toxic.

All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, thin fillm deposition using sputtering targets and evaporation materials, metallurgy and optical materials and other high technology applications. Information is provided for stable (non-radioactive) isotopesOrgano-Metallic Thallium compounds are soluble in organic or non-aqueous solvents. See Analytical Services for information on available certified chemical and physical analysis techniques including MS-ICP, X-Ray Diffraction, PSD and Surface Area (BET) analysis. 

Thallium was first discovered by Sir William Crookes in 1861. Thallium get its name from the Greek word "thallos" which means twig or green shoot.

Abundance. The following table shows the abundance of thallium and each of its naturally occurringisotopes on Earth along with the atomic mass for each isotope.
Isotope Atomic Mass % Abundance on Earth
Tl-203 202.972329 29.524
Tl-205 204.974412 70.476

The following table shows the abundance of Thallium present in the human body and in the universe scaled to parts per billion (ppb) by weight and by atom:
  Typical Human Body Universe
by Weight no data 0.5 ppb
by Atom no data 0.003 ppb

Safety Data and Biological Role. The safety data for thallium metalnanoparticles and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the left margin. Thallium compounds have no biological role. 

Ionization Energy. The ionization energy for thallium (the least required energy to release a single electron from the atom in it‘s ground state in the gas phase) is stated in the following table:
1st Ionization Energy 589.36 kJ mol-1
2nd Ionization Energy 1971.02 kJ mol-1
3rd Ionization Energy 2878.18 kJ mol-1

Conductivity. As to thallium‘s electrical and thermal conductivity, the electrical conductivity measured as to electrical resistivity @ 20 ?C is 18 μΩcm and its electronegativities (or its ability to draw electrons relative to other elements) is 1.8. The thermal conductivity of thallium is 46.1 W m-1 K-1. 

Thermal Properties. The melting point and boiling point for thallium are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization.
Heat of Fusion 4.31 kJ mol-1
Heat of Vaporization 166.1 kJ mol-1
Heat of Atomization 182.845 kJ mol-1

Formula Atomic Number Molecular Weight Electronegativity (Pauling) Density Melting Point Boiling Point Vanderwaals radius Ionic radius Energy of first ionization
Tl 81 204.383 g.mol-1 1.8 11.71 at 20 °C 1800 °C 4200 °C 0.099 nm (+3) 589.36 kJ.mol-1