Template:Infobox selenium

Selenium, 34Se
Selenium
Pronunciation/sɪˈlniəm/ (sə-LEE-nee-əm)
Appearancegrey metallic-looking, red, and vitreous black (not pictured) allotropes
Standard atomic weight Ar°(Se)
78.971(8)[1]
Selenium 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
S

Se

Te
arsenicseleniumbromine
Atomic number (Z)34
Groupgroup 16 (chalcogens)
Periodperiod 4
Block  p-block
Electron configuration[Ar] 3d10 4s2 4p4
Electrons per shell2, 8, 18, 6
Physical properties
Phase at STPsolid
Melting point494 K ​(221 °C, ​430 °F)
Boiling point958 K ​(685 °C, ​1265 °F)
Density (near r.t.)gray: 4.81 g/cm3
alpha: 4.39 g/cm3
vitreous: 4.28 g/cm3
when liquid (at m.p.)3.99 g/cm3
Critical point1766 K, 27.2 MPa
Heat of fusiongray: 6.69 kJ/mol
Heat of vaporization95.48 kJ/mol
Molar heat capacity25.363 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 500 552 617 704 813 958
Atomic properties
Oxidation states−2, −1, 0,[2] +1,[3] +2, +3, +4, +5, +6 (a strongly acidic oxide)
ElectronegativityPauling scale: 2.55
Ionization energies
  • 1st: 941.0 kJ/mol
  • 2nd: 2045 kJ/mol
  • 3rd: 2973.7 kJ/mol
Atomic radiusempirical: 120 pm
Covalent radius120±4 pm
Van der Waals radius190 pm
Color lines in a spectral range
Spectral lines of selenium
Other properties
Natural occurrenceprimordial
Crystal structuretrigonal
Trigonal crystal structure for selenium
Speed of sound thin rod3350 m/s (at 20 °C)
Thermal expansionamorphous: 37 µm/(m⋅K) (at 25 °C)
Thermal conductivityamorphous: 0.519 W/(m⋅K)
Magnetic orderingdiamagnetic[4]
Molar magnetic susceptibility−25.0×10−6 cm3/mol (298 K)[5]
Young's modulus10 GPa
Shear modulus3.7 GPa
Bulk modulus8.3 GPa
Poisson ratio0.33
Mohs hardness2.0
Brinell hardness736 MPa
CAS Number7782-49-2
History
Namingafter Selene, Greek goddess of the moon
Discovery and first isolationJöns Jakob Berzelius and Johann Gottlieb Gahn (1817)
Isotopes of selenium
Main isotopes[6] Decay
abun­dance half-life (t1/2) mode pro­duct
72Se synth 8.4 d ε 72As
γ
74Se 0.860% stable
75Se synth 119.8 d ε 75As
γ
76Se 9.23% stable
77Se 7.60% stable
78Se 23.7% stable
79Se trace 3.27×105 y β 79Br
80Se 49.8% stable
82Se 8.82% 1.08×1020 y ββ 82Kr
 Category: Selenium
| references
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 (11) · (this table: )

References

  1. "Standard Atomic Weights: Selenium". CIAAW. 2013.
  2. A Se(0) atom has been identified using DFT in [ReOSe(2-pySe)3]; see Cargnelutti, Roberta; Lang, Ernesto S.; Piquini, Paulo; Abram, Ulrich (2014). "Synthesis and structure of [ReOSe(2-Se-py)3]: A rhenium(V) complex with selenium(0) as a ligand". Inorganic Chemistry Communications. 45: 48–50. doi:10.1016/j.inoche.2014.04.003. ISSN 1387-7003.
  3. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  4. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  5. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  6. 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.