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For other uses, see [[:the noble gas]].
Neon, 10Ne
Neon
Appearancecolorless gas exhibiting an orange-red glow when placed in an electric field
Standard atomic weight Ar°(Ne)
Neon 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
He
↑
Ne
↓
Ar
fluorine ← neon → sodium
Atomic number (Z)10
Groupgroup 18 (noble gases)
Periodperiod 2
Block  p-block
Electron configuration[He] 2s2 2p6
Electrons per shell2, 8
Physical properties
Phase at STPgas
Melting point24.56 K ​(−248.59 °C, ​−415.46 °F)
Boiling point27.104 K ​(−246.046 °C, ​−410.883 °F)
Density (at STP)0.9002 g/L
when liquid (at b.p.)1.207 g/cm3[3]
Triple point24.556 K, ​43.37 kPa[4][5]
Critical point44.4918 K, 2.7686 MPa[5]
Heat of fusion0.335 kJ/mol
Heat of vaporization1.71 kJ/mol
Molar heat capacity20.79[6] J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 12 13 15 18 21 27
Atomic properties
Oxidation statescommon: (none)
0[7]
Ionization energies
  • 1st: 2080.7 kJ/mol
  • 2nd: 3952.3 kJ/mol
  • 3rd: 6122 kJ/mol
  • (more)
Covalent radius58 pm
Van der Waals radius154 pm
Color lines in a spectral range
Spectral lines of neon
Other properties
Natural occurrenceprimordial
Crystal structure ​face-centered cubic (fcc) (cF4)
Lattice constant
Face-centered cubic crystal structure for neon
a = 453.77 pm (at triple point)[8]
Thermal conductivity49.1×10−3 W/(m⋅K)
Magnetic orderingdiamagnetic[9]
Molar magnetic susceptibility−6.74×10−6 cm3/mol (298 K)[10]
Bulk modulus654 GPa
Speed of sound435 m/s (gas, at 0 °C)
CAS Number7440-01-9
History
PredictionWilliam Ramsay (1897)
Discovery and first isolationWilliam Ramsay & Morris Travers[11][12] (1898)
Isotopes of neon
Main isotopes[13] Decay
abun­dance half-life (t1/2) mode pro­duct
20Ne 90.5% stable
21Ne 0.27% stable
22Ne 9.25% stable
 Category: Neon
| references

Neon (Template:PronEng) is the chemical element that has the symbol Ne and atomic number 10. Although a very common element in the universe, it is rare on Earth. A colorless, inert noble gas under standard conditions, neon gives a distinct reddish-orange glow when used in discharge tubes and neon lamps.[14][15] It is commercially extracted from air, in which it is found in trace amounts.

History

Neon (Greek [νέον] Error: {{Lang}}: text has italic markup (help) (neon) meaning "new one") was discovered in 1898 by Scottish chemist Sir William Ramsay (1852–1916) English chemist Morris W. Travers (1872–1961) in London, England.[16] Neon was discovered when Ramsay chilled a sample of the atmosphere until it became a liquid, then warmed the liquid and captured the gases as they boiled off. The three gases that boiled off were krypton, xenon, and neon.[17] In December of 1910, French engineer Georges Claude made a lamp from an electrified tube of neon gas. On January 19, 1915, Claude began selling his tubes to U.S. companies; the Packard car dealership in Los Angeles was one of the first to buy it.[18]

Isotopes

Main article: Isotopes of neon

Neon has three stable isotopes: 20Ne (90.48%), 21Ne (0.27%) and 22Ne (9.25%). 21Ne and 22Ne are nucleogenic and their variations are well understood. In contrast, 20Ne is not known to be nucleogenic [citation needed] and the causes of its variation in the Earth have been hotly debated. The principal nuclear reactions which generate neon isotopes are neutron emission, alpha decay reactions on 24Mg and 25Mg, which produce 21Ne and 22Ne, respectively. The alpha particles are derived from uranium-series decay chains, while the neutrons are mostly produced by secondary reactions from alpha particles. The net result yields a trend towards lower 20Ne/22Ne and higher 21Ne/22Ne ratios observed in uranium-rich rocks such as granites. Isotopic analysis of exposed terrestrial rocks has demonstrated the cosmogenic production of 21Ne. This isotope is generated by spallation reactions on magnesium, sodium, silicon, and aluminium. By analyzing all three isotopes, the cosmogenic component can be resolved from magmatic neon and nucleogenic neon. This suggests that neon will be a useful tool in determining cosmic exposure ages of surficial rocks and meteorites.[19]

Similar to xenon, neon content observed in samples of volcanic gases are enriched in 20Ne, as well as nucleogenic 21Ne, relative to 22Ne content. The neon isotopic content of these mantle-derived samples represent a non-atmospheric source of neon. The 20Ne-enriched components are attributed to exotic primordial rare gas components in the Earth, possibly representing solar neon. Elevated 20Ne abundances are found in diamonds, further suggesting a solar neon reservoir in the Earth.[20]

Characteristics

Neon is the second-lightest noble gas. It glows reddish-orange in a vacuum discharge tube. According to recent studies, neon is the least reactive noble gas and thus the least reactive of all elements. Also, neon has the narrowest liquid range of any element: 2.51 C° (−248.59 °C to −246.08 °C) or 4.52 F° (−415.46 °F to −410.94 °F). It has over 40 times the refrigerating capacity of liquid helium and three times that of liquid hydrogen (on a per unit volume basis).[21] In most applications it is a less expensive refrigerant than helium.[22]

Spectrum of neon with ultraviolet lines (at left) and infrared (at right) shown in white

Neon plasma has the most intense light discharge at normal voltages and currents of all the noble gases. The average color of this light to the human eye is red-orange due to many lines in this range; it also contains a strong green line which is hidden, unless the visual components are dispersed by a spectroscope.[23]


Two quite different kinds of neon lights are in common use. Glow-discharge lamps are typically tiny, and often designed to operate at 120 volts; they are widely used as power-on indicators and in circuit-testing equipment. Neon signs and other arc-discharge devices operate instead at high voltages, often 3–15 kilovolts (3,000–15,000 volts); they can be made into (often bent) tubes a few meters long.

Occurrence

Neon is actually abundant on a universal scale: the fifth most abundant chemical element in the universe by mass, after hydrogen, helium, oxygen, and carbon (see chemical element). Its relative rarity on Earth, like that of helium, is due to its relative lightness and chemical inertness, both properties keeping it from being trapped in the condensing gas and dust clouds of the formation of smaller and warmer solid planets like Earth.

Neon is monatomic, making it lighter than the molecules of diatomic nitrogen and oxygen which form the bulk of Earth's atmosphere; a balloon filled with neon will rise up into the air, albeit more slowly than a helium balloon.[24]

Mass abundance in the universe is about 1 part in 750 and in the Sun and presumably in the proto-solar system nebula, about 1 part in 600. The Galileo spacecraft atmospheric entry probe found that even in the upper atmosphere of Jupiter, neon is reduced by about a factor of 10, to 1 part in 6,000 by mass. This may indicate that even the ice-planetesmals which brought neon into Jupiter from the outer solar system, formed in a region which was too warm for them to have kept their neon (abundances of heavier inert gases on Jupiter are several times that found in the Sun).[25]

Neon is a monatomic gas at standard conditions. Neon is rare on Earth, found in the Earth's atmosphere at 1 part in 65,000 (by volume) or 1 part in 83,000 by mass. It is industrially produced by cryogenic fractional distillation of liquefied air.[26]

Applications

A neon sign in the shape of its name.

Neon is often used in signs and produces an unmistakable bright reddish-orange light. Although still referred to as "neon", all other colors are generated with the other Noble Gases or by many colors of fluorescent lighting.

Neon is used in vacuum tubes, high-voltage indicators, lightning arrestors, wave meter tubes, television tubes, and helium-neon lasers. Liquefied neon is commercially used as a cryogenic refrigerant in applications not requiring the lower temperature range attainable with more extreme liquid helium refrigeration.

Liquid neon is actually quite expensive, and nearly impossible to obtain in small quantities for laboratory tests. For small quantities, liquid neon can be >55x more expensive than liquid helium. The driver for expense is actually rarity of the gas, not the liquefaction process.

The triple point temperature of Neon (24.5561 K) is a defining fixed point in the International Temperature Scale of 1990.[4]

Compounds

Neon is the first p-block noble gas. Theoretically neon is the least reactive of all noble gases (including helium which produces a metastable compound HHeF), and therefore generally considered to be inert. The calculated bond energies of neon with noble metals, hydrogen, berylium and boron are lesser than that of helium or any other noble gas. No true compounds including the neutral compounds of neon are known. However, the ions Ne+, (NeAr)+, (NeH)+, and (HeNe+) have been observed from optical and mass spectrometric studies, and neon is also known to form an unstable hydrate.[27]

See also

References

  1. ^ "Standard Atomic Weights: Neon". CIAAW. 1985.
  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. ^ Hammond, C. R. (2000). The Elements, in Handbook of Chemistry and Physics 81st edition (PDF). CRC press. p. 19. ISBN 0849304814.
  4. ^ a b Preston-Thomas, H. (1990). "The International Temperature Scale of 1990 (ITS-90)". Metrologia. 27 (1): 3–10. Bibcode:1990Metro..27....3P. doi:10.1088/0026-1394/27/1/002. Cite error: The named reference "ITS90" was defined multiple times with different content (see the help page).
  5. ^ a b Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, Florida: CRC Press. p. 4.122. ISBN 1-4398-5511-0.
  6. ^ Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases". in Kirk Othmer Encyclopedia of Chemical Technology, pages 343–383. Wiley. doi:10.1002/0471238961.0701190508230114.a01.pub2
  7. ^ Ne(0) has been observed in Cr(CO)5Ne; see Perutz, Robin N.; Turner, James J. (August 1975). "Photochemistry of the Group 6 hexacarbonyls in low-temperature matrices. III. Interaction of the pentacarbonyls with noble gases and other matrices". Journal of the American Chemical Society. 97 (17): 4791–4800. doi:10.1021/ja00850a001.
  8. ^ Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  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.
  10. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  11. ^ Ramsay, William; Travers, Morris W. (1898). "On the Companions of Argon". Proceedings of the Royal Society of London. 63 (1): 437–440. doi:10.1098/rspl.1898.0057. ISSN 0370-1662. S2CID 98818445.
  12. ^ "Neon: History". Softciências. Retrieved 2007-02-27.
  13. ^ 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.
  14. ^ Harold P Coyle (2001). Project STAR: The Universe in Your Hands. Kendall Hunt. ISBN 9780787267636.
  15. ^ Kohtaro Kohmoto (1999). "Phosphors for lamps". In Shigeo Shionoya and William M. Yen (ed.). Phosphor Handbook. CRC Press. ISBN 9780849375606.
  16. ^ William Ramsay, Morris W. Travers (1898). "On the Companions of Argon". Proceedings of the Royal Society of London. 63: 437–440. doi:10.1098/rspl.1898.0057.
  17. ^ "Neon: History". Softciências. Retrieved 2007-02-27.
  18. ^ "Neon: A Brief History". New York Magazine. Retrieved 2008-05-20.
  19. ^ "Neon: Isotopes". Softciências. Retrieved 2007-02-27.
  20. ^ Anderson, Don L. "Helium, Neon & Argon". Mantleplumes.org. Retrieved 2006-07-02.
  21. ^ "Neon". Los Almos National Laboratory. 15. Retrieved 2007-03-05. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |month= ignored (help)
  22. ^ "NASSMC: News Bulletin". 30. Retrieved 2007-03-05. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |month= ignored (help)
  23. ^ "Plasma". Retrieved 2007-03-05.
  24. ^ R. Gallagher and P. Ingram (2001). Chemistry for Higher Tier. University Press. ISBN 9780199148172.
  25. ^ Morse, David (26). "Galileo Probe Science Result". Galileo Project. Retrieved 2007-02-27. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help); Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
  26. ^ Hammond, C. R. "The Elements" (PDF). Fermi National Accelerator Lab. p. 19. Retrieved 2007-02-27. {{cite web}}: Cite has empty unknown parameters: |month= and |coauthors= (help)
  27. ^ "Periodic Table: Neon." Lawrence Livermore National Laboratory. Last updated on December 15, 2003. Retrieved on August 31, 2007.
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