Group: 18 or VIII A
Atomic Weight: 20.1797
CAS Number: 7440-01-9
No Stable Isotopes
Description • Uses/Function
Discovered by Ramsay and Travers in 1898. Neon is a rare gaseous element present in the atmosphereto the extent of 1 part in 65,000 of air. It is obtained by liquefaction of air and separated from the other gases by fractional distillation. Natural neonis a mixture of three isotopes. Six other unstable isotopes are known. It is very inert element; however, it is said to form a compound with fluorine.It is still questionable if true compounds of neon exist, but evidence is mounting in favor of their existence. The following ions are known from opticaland mass spectrometric studies: Ne+, (NeAr)+, (NeH)+, and (HeNe+). Neon also forms an unstable hydrate. In a vacuum discharge tube, neon glowsreddish orange. Of all the rare gases, the discharge of neon is the most intense at ordinary voltages and currents. Neon is used in making the commonneon advertising signs, which accounts for its largest use. It is also used to make high-voltage indicators, lightning arrestors, wave meter tubes, andTV tubes. Neon and helium are used in making gas lasers. Liquid neon is now commercially available and is finding important application as aneconomical cryogenic refrigerant. It has over 40 times more refrigerating capacity per unit volume than liquid helium and more than three times thatof liquid hydrogen. It is compact, inert, and is less expensive than helium when it meets refrigeration requirements. Neon costs about $800/80 cu. ft.(2265 L). 1
• "Neon signs" 2
• "The French chemist Georges Claude (1870-1960) worked with neon vapor lamps; beginning in 1927, he was able to produce them in quantity. Vapor lamps containing a variety of different gases of gas mixtures could be bent into attractive shapes, or into letters that spelled out words (and usually carried an advertising message). So prominent was the red color of those vapor lamps containing neon that all of them, whether they actually contained neon or not, came to be called neon lights.
A small, dim version of the neon light is the neon glow lamp, which consists of a small bulb containing electrodes in a neon atmosphere. Electricity is forced through the neon, causing it to produce a red glow. Little electricity is required for the purpose, and the lamp is not really intended for illumination, but merely as a signal - to indicate the location of a switch or to act as evidence that some electric circuit is in working order (or, perhaps, is not in working order).
In 1957, the spark chamber was introduced for the detection of subatomic particles, and proved to be more efficient for many purposes than the older detection devices. The spark chamber consists of closely spaced metal plates, with alternate plates highly charged with electricity, so that an electric spark is at the point of being released. When a subatomic particle speeds through, sparks are released at the points where it strikes the plates. Between the plates of this device an inert gas is used, either neon or argon.
Efforts were made at once to produce continuous lasers, and the ruby was replaced by tubes of gas. The gas lasers so produced, later in 1960, were continuous. The gases used in such lasers include all of the stable noble gases, alone or in combination. The first gas laser, produced by the Iranian physicist Ali Javan (b. 1926), working at Bell Telephone Laboratories, made use of a mixture of neon and helium. This variety is still the most important." 3
Melting Point:4* -248.59 °C = 24.56 K = -415.462 °F
Boiling Point:4* -246.08 °C = 27.07 K = -410.944 °F
Critical Point:4 -228.7 °C = 44.45 K = -379.66 °F 4
Density:5 0.825 g/L
* - at 1 atm
Electron Configuration: [He] 2s2 2p6
Highest Occupied Energy Level: 2
Valence Electrons: 8
n = 2
ℓ = 1
mℓ = 1
ms = -½
Electron Affinity:6 not stable eV
Oxidation States: 0
|Ionization Potential||eV 7||kJ/mol|
|Ionization Potential||eV 7||kJ/mol|
|Ionization Potential||eV 7||kJ/mol|
Specific Heat: 1.030 J/g°C 8 = 20.785 J/mol°C = 0.246 cal/g°C = 4.968 cal/mol°C
Heat of Fusion: 0.3317 kJ/mol 10 = 16.4 J/g
Heat of Vaporization: 1.7326 kJ/mol 11 = 85.9 J/g
|State of Matter||Enthalpy of Formation (ΔHf°)12||Entropy (S°)12||Gibbs Free Energy (ΔGf°)12|
|Nuclide||Mass 13||Half-Life 13||Nuclear Spin 13||Binding Energy|
|16Ne||16.025761(22)||9E-21 s [122(37) keV]||0+||98.03 MeV|
|17Ne||17.017672(29)||109.2(6) ms||1/2-||113.55 MeV|
|18Ne||18.0057082(3)||1.672(8) s||0+||132.80 MeV|
|19Ne||19.0018802(3)||17.296(5) s||1/2+||144.60 MeV|
|23Ne||22.99446690(11)||37.24(12) s||5/2+||183.41 MeV|
|24Ne||23.9936108(4)||3.38(2) min||0+||192.41 MeV|
|25Ne||24.997737(28)||602(8) ms||(3/2)+||196.75 MeV|
|26Ne||26.000461(29)||197(1) ms||0+||202.03 MeV|
|27Ne||27.00759(12)||32(2) ms||(3/2+)#||203.58 MeV|
|28Ne||28.01207(16)||18.3(22) ms||0+||207.00 MeV|
|29Ne||29.01939(29)||15.6(5) ms||(3/2+)#||208.55 MeV|
|30Ne||30.02480(61)||5.8(2) ms||0+||211.96 MeV|
|31Ne||31.03311(97)#||3.4(8) ms||7/2-#||211.65 MeV|
|32Ne||32.04002(86)#||3.5(9) ms||0+||213.20 MeV|
|33Ne||33.04938(86)#||<260 ns||7/2-#||212.89 MeV|
|34Ne||34.05703(87)#||1# ms [>1.5 μs]||0+||213.51 MeV|
|Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 13|
Earth - Source Compounds: uncombined 14
Earth - Seawater: 0.00012 mg/L 15
Earth - Crust: 0.005 mg/kg = 0.0000005% 15
Earth - Total: 0.50E-8 cm^3/g 16
Mercury - Total: 16
Venus - Total: 49E-8 cm^3/g 16
Chondrites - Total: 0.0015 (relative to 106 atoms of Si) 17
Material Safety Data Sheet - ACI Alloys, Inc.
For More Information
Chemical & Engineering News
HyperPhysics from Georgia State University's Department of Physics and Astronomy
Los Alamos National Laboratory
Physics Department of the University of Coimbra
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(3) - Asimov, Isaac. The Noble Gases; Basic Books, Inc.: New York City, 1966; pp 86-88.
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(12) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(13) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(14) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(16) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(17) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.