Argon, 18 Ar Vial containing a violet glowing gas Pronunciation (AR -gon ) Appearance colorless gas exhibiting a lilac/violet glow when placed in an electric field
Atomic number (Z ) 18 Group group 18 (noble gases) Period period 3 Block p-block Electron configuration [Ne ] 3s2 3p6 Electrons per shell 2, 8, 8 Phase at STP gas Melting point 83.81 K (−189.34 °C, −308.81 °F) Boiling point 87.302 K (−185.848 °C, −302.526 °F) Density (at STP) 1.784 g/L when liquid (at b.p. ) 1.3954 g/cm3 Triple point 83.8058 K, 68.89 kPa[ 3] Critical point 150.687 K, 4.863 MPa[ 3] Heat of fusion 1.18 kJ/mol Heat of vaporization 6.53 kJ/mol Molar heat capacity 20.85[ 4] J/(mol·K) Vapor pressure
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
47
53
61
71
87
Oxidation states common: (none)
0[ 5] Electronegativity Pauling scale: no data Ionization energies 1st: 1520.6 kJ/mol 2nd: 2665.8 kJ/mol 3rd: 3931 kJ/mol (more ) Covalent radius 106±10 pm Van der Waals radius 188 pm Color lines in a spectral range Spectral lines of argonNatural occurrence primordial Crystal structure face-centered cubic (fcc) (cF4 ) Lattice constant a = 546.91 pm (at triple point)[ 6] Thermal conductivity 17.72× 10 −3 W/(m⋅K) Magnetic ordering diamagnetic [ 7] Molar magnetic susceptibility −19.6× 10−6 cm3 /mol[ 8] Speed of sound 323 m/s (gas, at 27 °C) CAS Number 7440-37-1 Naming from the Greek ἀργόν , meaning 'lazy' or 'inactive', in reference to its inertness Discovery and first isolationLord Rayleigh and William Ramsay (1894)
File:Symbol category class.svg Category: Argon | references
child table, as reused in {IB-Ar}
References
These references will appear in the article, but this list appears only on this page.
↑ "Standard Atomic Weights: Argon" . CIAAW . 2017.
↑ 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 .
↑ 3.0 3.1 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, Florida: CRC Press . p. 4.121. ISBN 1-4398-5511-0 .
↑ Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases". Kirk Othmer Encyclopedia of Chemical Technology. Wiley. pp. 343–383. doi:10.1002/0471238961.0701190508230114.a01.
↑ Ar(0) has been observed in argon fluorohydride (HArF) and ArCF2 2+ , see Lockyear, J.F.; Douglas, K.; Price, S.D.; Karwowska, M.; et al. (2010). "Generation of the ArCF2 2+ Dication". Journal of Physical Chemistry Letters . 1 : 358. doi :10.1021/jz900274p .
↑ Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements . Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9 .
↑ Magnetic susceptibility of the elements and inorganic compounds , in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0486-5 .
↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics . Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4 .
↑ 9.0 9.1 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 .
Two of these are named references . They may be cited in the containing article as
<ref name="CIAAW2016" /> for the source Atomic weights of the elements 2016 (from subtemplates used by {{ Infobox element }} )
<ref name="b92" /> for the source edited by Haynes
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