Krypton

This article is about the chemical element. For other uses, see Krypton (disambiguation).

Krypton, 36Kr
A krypton-filled discharge tube glowing white
Krypton
Pronunciation/ˈkrɪptɒn/ ​(KRIP-ton)
Appearancecolorless gas, exhibiting a whitish glow in an electric field
Standard atomic weight Ar°(Kr)
Krypton 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
Ar
↑
Kr
↓
Xe
bromine ← krypton → rubidium
Atomic number (Z)36
Groupgroup 18 (noble gases)
Periodperiod 4
Block  p-block
Electron configuration[Ar] 3d10 4s2 4p6
Electrons per shell2, 8, 18, 8
Physical properties
Phase at STPgas
Melting point115.78 K ​(−157.37 °C, ​−251.27 °F)
Boiling point119.93 K ​(−153.415 °C, ​−244.147 °F)
Density (at STP)3.749 g/L
when liquid (at b.p.)2.413 g/cm3[3]
Triple point115.775 K, ​73.53 kPa[4][5]
Critical point209.48 K, 5.525 MPa[5]
Heat of fusion1.64 kJ/mol
Heat of vaporization9.08 kJ/mol
Molar heat capacity20.95[6] J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 59 65 74 84 99 120
Atomic properties
Oxidation statescommon: +2
+1,? +2
ElectronegativityPauling scale: 3.00
Ionization energies
  • 1st: 1350.8 kJ/mol
  • 2nd: 2350.4 kJ/mol
  • 3rd: 3565 kJ/mol
Covalent radius116±4 pm
Van der Waals radius202 pm
Color lines in a spectral range
Spectral lines of krypton
Other properties
Natural occurrenceprimordial
Crystal structure ​face-centered cubic (fcc) (cF4)
Lattice constant
Face-centered cubic crystal structure for krypton
a = 583.57 pm (at triple point: 115.78 K)[7]
Thermal conductivity9.43×10−3  W/(m⋅K)
Magnetic orderingdiamagnetic[8]
Molar magnetic susceptibility−28.8×10−6 cm3/mol (298 K)[9]
Speed of sound(gas, 20 °C) 221 m·s−1
(liquid) 1120 m/s
CAS Number7439-90-9
History
Discovery and first isolationWilliam Ramsay and Morris Travers (1898)
Isotopes of krypton
Main isotopes[10] Decay
abun­dance half-life (t1/2) mode pro­duct
78Kr 0.360% 9.2×1021 y[11] εε 78Se
79Kr synth 35 h ε 79Br
β+ 79Br
γ –
80Kr 2.29% stable
81Kr trace 2.3×105 y ε 81Br
81mKr synth 13.10 s IT 81Kr
ε 81Br
82Kr 11.6% stable
83Kr 11.5% stable
84Kr 57.0% stable
85Kr trace 11 y β− 85Rb
86Kr 17.3% stable
 Category: Krypton
| references

Krypton (from Ancient Greek: κρυπτός, romanized: kryptos 'the hidden one') is a chemical element; it has symbol Kr and atomic number 36. It is a colorless, odorless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. Krypton is chemically inert.

Krypton, like the other noble gases, is used in lighting and photography. Krypton light has many spectral lines, and krypton plasma is useful in bright, high-powered gas lasers (krypton ion and excimer lasers), each of which resonates and amplifies a single spectral line. Krypton fluoride also makes a useful laser medium. From 1960 to 1983, the official definition of the metre was based on the wavelength of one spectral line of krypton-86, because of the high power and relative ease of operation of krypton discharge tubes.

  1. ^ "Standard Atomic Weights: Krypton". CIAAW. 2001.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ Krypton. encyclopedia.airliquide.com
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  7. ^ Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  8. ^ 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.
  9. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  10. ^ 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.
  11. ^ Patrignani, C.; et al. (Particle Data Group) (2016). "Review of Particle Physics". Chinese Physics C. 40 (10): 100001. Bibcode:2016ChPhC..40j0001P. doi:10.1088/1674-1137/40/10/100001. See p. 768