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Selenium
Selenium information, including Technical Data, Safety Data and its 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

 

  Hydrogen                                 Helium
  Lithium Beryllium                     Boron Carbon Nitrogen Oxygen Fluorine Neon
  Sodium Magnesium                     Aluminum Silicon Phosphorus Sulfur Chlorine Argon
  Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Hydrogen 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
  Cesium Barium Cerium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon
                                     
      Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium    
      Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawerencium    


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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 nanopowders provide 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. 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.

French Sélénium German Selen Italian Selenio Portuguese Selênio Spanish Selenio Swedish Selen

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.

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 UK Operations Submicron & Nanopowder Tolling Ultra High Purity Sputtering Target Crystal Growth Rod, Plate, Powder, etc. Foil
 
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Recent Research & Development for Selenium

  • Medical geology in tropical countries with special reference to Sri Lanka.
    Environ Geochem Health. 2007 Jan 26; [Epub ahead of print]

  • Antioxidant treatment for amyotrophic lateral sclerosis / motor neuron disease.
    Cochrane Database Syst Rev. 2007 Jan 24;(1):CD002829.

  • Contaminants in Lesser and Greater Scaup Staging on the Lower Great Lakes.
    Arch Environ Contam Toxicol. 2007 Jan 25; [Epub ahead of print]

  • Lewis acid catalyzed ring-opening reactions of methylenecyclopropanes with diphenylphosphine oxide in the presence of sulfur or selenium.
    Org Biomol Chem. 2007 Feb 7;5(3):438-40. Epub 2006 Dec 14.

  • Selenium status in Southern Tasmania.
    Eur J Clin Nutr. 2007 Jan 24; [Epub ahead of print]

  • Supplementation with vitamins C, E, beta-carotene and selenium has no effect on anti-oxidant status and immune responses in allergic adults: a randomized controlled trial.
    Clin Exp Allergy. 2007 Feb;37(2):180-7.

  • Neuronal and ependymal expression of selenoprotein P in the human brain.
    J Neural Transm. 2007 Jan 25; [Epub ahead of print]

  • Seasonal fluctuations of selenium and sulfur accumulation in selenium hyperaccumulators and related nonaccumulators.
    New Phytol. 2007;173(3):517-25.

  • An unusual myopathy: Speckled muscle fibers due to enlarged mitochondria.
    Muscle Nerve. 2007 Jan 22; [Epub ahead of print]

  • Enhanced tight junction function in human breast cancer cells by antioxidant, selenium and polyunsaturated lipid.
    J Cell Biochem. 2007 Jan 22; [Epub ahead of print]

 

 

 

 

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