Selenium information, including Technical Data, Safety Data and its high purity properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.
Selenium exhibits both photovoltaic action, where light is converted directly into electricity, and photoconductive action, where the electrical resistance decreases with increased illumination. These properties make selenium useful in the production of photocells and exposure meters for photographic use, as well as solar cells. Below its melting point, selenium is a p-type semiconductor and has many uses in electronic and solid-state applications. Selenium is available as metal 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. Selenium facts, including appearance, CAS #, and molecular formula and safety data, research and properties are
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. Selenium is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries. Selenium is a Block P, Group 16, Period 4 element. The electronic configuration is [Ar] 3d10 4s2 4p4. In its elemental form selenium's CAS number is 7782-49-2. The selenium atom has a radius of 116.pm and it's Van der Waals radius is 190.pm.All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, metallurgy and optical materials and other high technology advantages. Information is provided for stable (non-radioactive) isotopes. Organo-Metallic Selenium 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. Selenium was first discovered by Jons Berzelius in 1817.
Abundance. The following table shows the abundance of selenium and each of its naturally occurring isotopes on Earth along with the atomic mass for each isotope. |
Sélénium 
Selen 
Selenio
Selênio 
Selenio
Selen Isotope |
Atomic Mass |
% Abundance on Earth |
Se-74 |
73.922477 |
0.89 |
Se-76 |
75.919214 |
9.36 |
Se-77 |
76.919915 |
7.63 |
Se-78 |
77.917310 |
23.78 |
Se-80 |
79.916522 |
49.61 |
Se-82 |
81.916700 |
8.73 |
Safety Data. The safety data for selenium metal, nanoparticles 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.
Ionization Energy. The ionization energy for selenium (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 |
940.97 kJ mol-1 |
2nd Ionization Energy |
2044.54 kJ mol-1 |
3rd Ionization Energy |
2973.74 kJ mol-1 |
Conductivity. As to selenium's electrical and thermal conductivity, the electrical conductivity measured as to electrical resistivity @ 20 ºC is 12 μΩcm and its electronegativities (or its ability to draw electrons relative to other elements) is 2.55. The thermal conductivity of selenium is 2.04 W m-1 K-1.
Thermal Properties. The melting point and boiling point for selenium are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization. |
Heat of Fusion |
5.1 kJ mol-1 |
Heat of Vaporization |
90 kJ mol-1 |
Heat of Atomization |
226.4 kJ mol-1 |
| Formula | Atomic Number | Molecular Weight | Electronegativity (Pauling) | Density | Melting Point | Boiling Point |
Vanderwaals radius |
Ionic radius | Energy of first ionization |
| Se | 34 | 78.96 g.mol -1 | 2.4 | 4.79 g.cm-3 at 20 °C | 217 °C | 688 °C | 190.pm | 0.198 nm (-2) ; 0.042 (+6) | 940.97 kJ.mol-1 |
| PRODUCT CATALOG | U.S. Operations | Submicron & Nanopowder | Tolling | Ultra High Purity | Sputtering Target | Crystal Growth | Rod, Plate, Powder, etc. | Foil |
