| Atomic Mass | 20.1797 |
|---|---|
| Electron Configuration | [He]2s22p6 |
| Oxidation States | 0 |
| Year Discovered | 1898 |
| Atomic Mass | 20.1797 |
|---|---|
| Electron Configuration | [He]2s22p6 |
| Oxidation States | 0 |
| Year Discovered | 1898 |
| Element Name | Neon |
|---|---|
| Element Symbol | Ne |
| InChI | InChI=1S/Ne |
| InChIKey | GKAOGPIIYCISHV-UHFFFAOYSA-N |
| Atomic Weight |
20.1797(6) 20.1797 20.18 20.1797(6) |
|---|---|
| Electron Configuration |
[He]2s22p6 |
| Atomic Radius |
Van der Waals Atomic Radius : 154 pm (Van der Waals) Covalent Atomic Radius : 58 pm (Covalent) |
| Oxidation States |
|
| Ground Level |
1S0 |
| Ionization Energy |
21.565 eV 21.564541 ± 0.000007 eV |
| Electronegativity |
Allen Scale Electronegativity : 4.787(Allen Scale) |
| Electron Affinity |
0eV -0.3eV |
| Atomic Spectra |
Lines Holdings Levels Holdings |
| Physical Description |
Gas |
| Element Classification |
Non-metal |
| Element Period Number |
2 |
| Element Group Number |
18 - Noble Gas |
| Density |
0.0008999 grams per cubic centimeter |
| Melting Point |
24.56 K (-248.59°C or -415.46°F) -258.59°C |
| Boiling Point |
27.07 K (-246.08°C or -410.94°F) -246.046°C |
| Estimated Crustal Abundance |
5×10-3 milligrams per kilogram |
| Estimated Oceanic Abundance |
1.2×10-4 milligrams per liter |
The name derives from the Greek neos for "new". It was discovered from its bright orange spectral lines by the Scottish chemist William Ramsay and the English chemist Morris William Travers in 1898 from a liquefied air sample.
Neon was discovered by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist, shortly after their discovery of the element krypton in 1898. Like krypton, neon was discovered through the study of liquefied air. Although neon is the fourth most abundant element in the universe, only 0.0018% of the earth's atmosphere is neon.
From the Greek word neos, new. Discovered by Ramsay and Travers in 1898. Neon is a rare gaseous element present in the atmosphere to 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.
| Year | Atomic Weight (uncertainty) [u] | Reference |
|---|---|---|
| 1985 | 20.1797(6) | https://doi.org/10.1351/pac198658121677 |
| 1979 | 20.179(1) | https://doi.org/10.1351/pac198052102349 |
| 1967 | 20.179(3) | https://doi.org/10.1351/pac196918040569 |
| 1931 | 20.183 | https://doi.org/10.1039/JR9310001617 |
| 1911 | 20.2 | https://doi.org/10.1021/ja01928a001 |
| 1909 | 20.0 | https://doi.org/10.1021/ja01931a001 |
| 1902 | 20 | https://doi.org/10.1007/BF01370337 |
| Year | Isotope | Abundance (uncertainty) | Reference |
|---|---|---|---|
| 1989 | 20Ne | 0.9048(3) | https://doi.org/10.1351/pac199163070991 |
| 1989 | 21Ne | 0.0027(1) | https://doi.org/10.1351/pac199163070991 |
| 1989 | 22Ne | 0.0925(3) | https://doi.org/10.1351/pac199163070991 |
| 1981 | 20Ne | 0.9051(9) | https://doi.org/10.1351/pac198355071119 |
| 1981 | 21Ne | 0.0027(2) | https://doi.org/10.1351/pac198355071119 |
| 1981 | 22Ne | 0.0922(9) | https://doi.org/10.1351/pac198355071119 |
| 1979 | 20Ne | 0.9051(3) | https://doi.org/10.1351/pac198052102349 |
| 1979 | 21Ne | 0.0027(1) | https://doi.org/10.1351/pac198052102349 |
| 1979 | 22Ne | 0.0922(3) | https://doi.org/10.1351/pac198052102349 |
| 1975 | 20Ne | 0.9051 | https://doi.org/10.1351/pac197647010075 |
| 1975 | 21Ne | 0.0027 | https://doi.org/10.1351/pac197647010075 |
| 1975 | 22Ne | 0.0922 | https://doi.org/10.1351/pac197647010075 |
The largest use for neon gas is in advertising signs. Neon is also used to make high voltage indicators and is combined with helium to make helium-neon lasers. Liquid neon is used as a cryogenic refrigerant. Neon is highly inert and forms no known compounds, although there is some evidence that it could form a compound with fluorine.
Although neon advertising signs account for the bulk of its use, neon also functions in high-voltage indicators, lightning arrestors, wave meter tubes, and TV tubes. Neon and helium are used in making gas lasers. Liquid neon is now commercially available and is finding important application as an economical cryogenic refrigerant.
Neon is a very inert element, however, it has been reported 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 ions, Ne+, (NeAr)+, (NeH)+, and (HeNe+) are known from optical and mass spectrometric studies. Neon also forms an unstable hydrate.
See more information at the Neon compound page.
| CID | Name | Formula | SMILES | Molecular Weight |
|---|---|---|---|---|
| 23935 | neon | Ne | [Ne] | 20.180 |
| 10197602 | neon-20 | Ne | [20Ne] | 19.99244018 |
| 53393498 | neon-22 | Ne | [22Ne] | 21.9913851 |
| 71309521 | neon-21 | Ne | [21Ne] | 20.9938467 |
| 44154677 | neon-19 | Ne | [19Ne] | 19.001881 |
| Stable Isotope Count | 3 |
|---|---|
| Summary | Natural neon is a mixture of three isotopes. Six other unstable isotopes are known. |
Neon is subject to stable isotopic fractionation by physical processes, such as exchange between gas, liquid, and solid phases. Small variations in the isotope-amount ratio n(22Ne)/n(20Ne) have been used to examine gas-liquid exchange processes during groundwater recharge (water moving downward from the surface) and discharge [29], [101], [102].
Some 21Ne and 22Ne form naturally in the Earth’s crust largely by reactions of 18O and 19F in minerals with neutrons and alpha particles emitted from uranium and thorium decay, called nucleogenic neon isotopes [29], [101]. In addition, neon isotopes can form at the surface of the Earth and in extraterrestrial bodies by cosmic-ray-induced spallation reactions on magnesium, silicon, aluminum, and sodium [103], [104]. Analyses of all three stable neon isotopes may be used to distinguish these sources from primordial neon. The relative amounts of atmospheric neon and crustal nucleogenic neon isotopes in deep groundwaters and natural gases have been used in studies of solid-water-gas interactions and migration (Fig. IUPAC.10.1). The cosmogenic component is mainly detected in 21Ne and can be used to determine cosmic-ray exposure ages of rock samples, including meteorites exposed during travel through space and boulders exposed by melting of glacial ice (Fig. IUPAC.10.1).
![Fig. IUPAC.10.1: Neon-isotope ratios of water from fractures in quartzite (open diamonds) and water from fractures in vein quartz (solid circles) from the deep gold mines of the Witwatersrand Basin, South Africa [105]. The isotope-amount ratio n(²¹Ne)/n(²²Ne) depends upon the amount ratio of oxygen to fluorine in the ~40-μm reaction range of alpha particles from uranium and thorium. Lippmann-Pipke et al. [105] show that the neon end-member represents a fluorine-depleted fluid component that was trapped in fluid inclusions in vein quartz more than 2×10⁹ years ago.](https://pubchem.ncbi.nlm.nih.gov/images/iupac/j_pac-2015-0703_fig_022.jpg)
Masers (Microwave Amplification by Stimulated Emission of Radiation) containing 20Ne have been used to study quantum physics. 21Ne may also play a role in maser studies of quantum physics [106].
22Ne is used to produce the radioisotope 22Na via the reaction 22Ne (p, n) 22Na [107]. 20Ne has been used to produce the radioisotope 18F via the reaction 20Ne (d, 4He) 18F [107].
| Isotope | Atomic Mass (uncertainty) [u] | Abundance (uncertainty) |
|---|---|---|
| 20Ne | 19.992 440 18(1) | 0.9048(3) |
| 21Ne | 20.993 8467(3) | 0.0027(1) |
| 22Ne | 21.991 3851(1) | 0.0925(3) |
| Isotope | Atomic Mass (uncertainty) [u] | Abundance (uncertainty) |
|---|---|---|
| 20Ne | 19.9924401762(17) | 0.9048(3) |
| 21Ne | 20.993846685(41) | 0.0027(1) |
| 22Ne | 21.991385114(18) | 0.0925(3) |
| Nuclide | Atomic Mass and Uncertainty [u] | Half Life and Uncertainty | Discovery Year | Decay Modes, Intensities and Uncertainties [%] |
|---|---|---|---|---|
| 15Ne | 15.043172977 ± 0.000071588 | 770 ys ± 300 | 2014 | 2p=100% |
| 16Ne | 16.025750860 ± 0.000021986 | >5.7 zs | 1977 | 2p=100% |
| 17Ne | 17.017713962 ± 0.00000038 | 109.2 ms ± 0.6 | 1963 | β+=100%; β+p=94.4±2.9%; β+α=3.51±0.1%; β+pα=0.014±0.4% |
| 18Ne | 18.005708696 ± 0.00000039 | 1664.20 ms ± 0.47 | 1954 | β+=100% |
| 19Ne | 19.001880906 ± 0.000000171 | 17.2569 s ± 0.0019 | 1939 | β+=100% |
| 20Ne | 19.99244017525 ± 0.00000000165 | Stable | 1913 | IS=90.48±0.3% |
| 21Ne | 20.993846685 ± 0.000000041 | Stable | 1928 | IS=0.27±0.1% |
| 22Ne | 21.991385113 ± 0.000000018 | Stable | 1913 | IS=9.25±0.3% |
| 23Ne | 22.994466905 ± 0.000000112 | 37.15 s ± 0.03 | 1936 | β-=100% |
| 24Ne | 23.993610649 ± 0.00000055 | 3.38 m ± 0.02 | 1956 | β-=100[gs=0,m=100] |
| 25Ne | 24.997814797 ± 0.000031181 | 602 ms ± 8 | 1970 | β-=100% |
| 26Ne | 26.000516496 ± 0.000019784 | 197 ms ± 2 | 1970 | β-=100%; β-n=0.13±0.3% |
| 27Ne | 27.007569462 ± 0.000097445 | 30.9 ms ± 1.1 | 1977 | β-=100%; β-n=2.0±0.5%; β-2n ? |
| 28Ne | 28.012130767 ± 0.000135339 | 18.8 ms ± 0.2 | 1979 | β-=100%; β-n=12±0.1%; β-2n=3.7±0.5% |
| 29Ne | 29.019753000 ± 0.0001605 | 14.7 ms ± 0.4 | 1985 | β-=100%; β-n=28±0.5%; β-2n=4±0.1% |
| 30Ne | 30.024992235 ± 0.000271875 | 7.22 ms ± 0.18 | 1985 | β-=100%; β-n=13±0.4%; β-2n=8.9±2.3% |
| 31Ne | 31.033474816 ± 0.000285772 | 3.4 ms ± 0.8 | 1996 | β-=100%; β-n ?; β-2n ? |
| 32Ne | 32.039720 ± 0.00054 [Estimated] | 3.5 ms ± 0.9 | 1990 | β-=100%; β-n ?; β-2n ? |
| 33Ne | 33.049523 ± 0.000644 [Estimated] | Not-specified <260ns | n ? | |
| 34Ne | 34.056728 ± 0.000551 [Estimated] | 2 ms >1.5us [Estimated] | 2002 | β- ?; β-2n ?; β-n ? |
