Neon

For other uses, see Neon (disambiguation).
General Name, Symbol, Number neon, Ne, 10 Chemical series noble gases Group, Period, Block 18, 2, p Appearance colorless
Atomic mass 20.1797(6) g/mol Electron configuration 1s2 2s2 2p6 Electrons per shell 2, 8 Physical properties Phase gas Density (0 °C, 101.325 kPa)
0.9002 g/L Melting point 24.56 K
(-248.59 °C, -415.46 °F) Boiling point 27.07 K
(-246.08 °C, -410.94 °F) Heat of fusion 0.335 kJ/mol Heat of vaporization 1.71 kJ/mol Heat capacity (25 °C) 20.786 J/(mol·K) Atomic properties Crystal structure cubic face centered Oxidation states no data Ionization energies
(more) 1st: 2080.7 kJ/mol 2nd: 3952.3 kJ/mol 3rd: 6122 kJ/mol Atomic radius (calc.) 38 pm Covalent radius 69 pm Van der Waals radius 154 pm Miscellaneous Magnetic ordering nonmagnetic Thermal conductivity (300 K) 49.1 mW/(m·K) Speed of sound (gas, 0 °C) 435 m/s CAS registry number 7440-01-9 Notable isotopes References

Neon is the chemical element in the periodic table that has the symbol Ne and atomic number 10. A colorless nearly inert noble gas, neon gives a distinct reddish glow when used in vacuum discharge tubes and neon lamps and is found in air in trace amounts.

Notable characteristics

Neon is the second-lightest noble gas, glows reddish-orange in a vacuum discharge tube and has over 40 times the refrigerating capacity of liquid helium and three times that of liquid hydrogen (on a per unit volume basis). In most applications it is a less expensive refrigerant than helium. Neon has the most intense discharge at normal voltages and currents of all the rare gases.

Applications

Neon is often used in signs

The reddish-orange color that neon emits in neon lights is widely used to make advertising signs. The word "neon" is also used generically for these types of lights when in reality many other gases are used to produce different colors of light. Other uses:

History

Neon (Greek neos meaning "new") was discovered by Scottish chemist William Ramsay and English chemist Morris Travers in 1898.

Occurrence

Neon is usually found in the form of a gas with molecules consisting of a single neon atom. Neon is a rare gas that is found in the Earth's atmosphere at 1 part in 65,000 and is produced by supercooling air and fractionally distilling it from the resulting cryogenic liquid. Neon, like water vapor, is lighter than air; unlike water vapor, which condenses into a liquid below the stratosphere and is thus trapped in Earth's atmosphere, neon may slowly leak out into space, which explains its scarcity on Earth. Argon, in contrast, is heavier than air and so remains within Earth's atmosphere.

Compounds

The ions, Ne+, (NeAr)+, (NeH)+, and (HeNe+), have been observed from optical and mass spectrometric research. In addition, neon forms an unstable hydrate.

Isotopes

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 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.

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 also found in diamonds, further suggesting a solar neon reservoir in the Earth.

References


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Elevated 20Ne abundances are also found in diamonds, further suggesting a solar neon reservoir in the Earth. The Gilson opals often seen in vintage jewellery are actually an imitation consisting of laminated glass with bits of foil interspersed. The 20Ne-enriched components are attributed to exotic primordial rare gas components in the Earth, possibly representing solar neon. Most so-called synthetics, however, are more correctly termed imitations, as they contain substances not found in natural opal (e.g., plastic stabilizers). The neon isotopic content of these mantle-derived samples represent a non-atmospheric source of neon. Two notable producers of synthetic opal are the companies Kyocera and Inamori of Japan. Similar to xenon, neon content observed in samples of volcanic gases are enriched in 20Ne, as well as nucleogenic 21Ne, relative to 22Ne content. Synthetics are also generally lower in density and are often highly porous; some may even stick to the tongue.

This suggests that neon will be a useful tool in determining cosmic exposure ages of surficial rocks and meteorites. Synthetics are further distinguished from naturals by the former's lack of fluorescence under UV light. By analyzing all three isotopes, the cosmogenic component can be resolved from magmatic neon and nucleogenic neon. The resulting material is distinguishable from natural opal by its regularity; under magnification, the patches of colour are seen to be arranged in a "lizard skin" or "chicken wire" pattern. This isotope is generated by spallation reactions on magnesium, sodium, silicon, and aluminium. The discovery of the ordered sphere structure of precious opal led to its synthesis by Pierre Gilson in 1974 (Klein and Hurlbut, 1985, p.528). Isotopic analysis of exposed terrestrial rocks has demonstrated the cosmogenic production of 21Ne. As well as occurring naturally, opals of all varieties have been synthesized experimentally and commercially.

The net result yields a trend towards lower 20Ne/22Ne and higher 21Ne/22Ne ratios observed in uranium-rich rocks such as granites. The state gem stone for Nevada is precious black opal, which is named for the true black opal found in Virgin Valley, Humboldt County, Nevada. The alpha particles are derived from uranium-series decay chains, while the neutrons are mostly produced by secondary reactions from alpha particles. Opal is the official birthstone of the month of October. 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 opal is the official gemstone of South Australia. In contrast, 20Ne is not known to be nucleogenic and the causes of its variation in the Earth have been hotly debated. As a result, most of the production goes into the making of doublets and triplets.

21Ne and 22Ne are nucleogenic and their variations are well understood. A high percentage of the opal found there occurs in thin layers. Neon has three stable isotopes: 20Ne (90.48%), 21Ne (0.27%) and 22Ne (9.25%). A source of white base opal in the United States is Spencer, Idaho. In addition, neon forms an unstable hydrate. Boulder opal has a main source in Quilpie, Queensland. The ions, Ne+, (NeAr)+, (NeH)+, and (HeNe+), have been observed from optical and mass spectrometric research. Another Australian town, Lightning Ridge in New South Wales, is the main source of black opal, opal containing a predominantly dark background (dark-gray to blue-black displaying the play of color).

Argon, in contrast, is heavier than air and so remains within Earth's atmosphere. Common, water, jelly, and fire opal are found mostly in Mexico and Mesoamerica. Neon, like water vapor, is lighter than air; unlike water vapor, which condenses into a liquid below the stratosphere and is thus trapped in Earth's atmosphere, neon may slowly leak out into space, which explains its scarcity on Earth. In particular, the town of Coober Pedy in South Australia is a major source. Neon is a rare gas that is found in the Earth's atmosphere at 1 part in 65,000 and is produced by supercooling air and fractionally distilling it from the resulting cryogenic liquid. About 95% of the world's opal comes from Australia. Neon is usually found in the form of a gas with molecules consisting of a single neon atom. The resulting fossils, though not of any extra scientific interest, appeal to collectors.

Neon (Greek neos meaning "new") was discovered by Scottish chemist William Ramsay and English chemist Morris Travers in 1898. Opal is one of the mineraloids that can form or replace fossils. Other uses:. Opal is a mineraloid gel which is deposited at relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, and basalt. The word "neon" is also used generically for these types of lights when in reality many other gases are used to produce different colors of light. Besides the gemstone varieties that show a play of color, there are other kinds of common opal such as the milk opal, milky bluish to greenish; resin opal, honey-yellow with a resinous lustre; wood opal, caused by the replacement of the organic material in wood with opal; menilite brown or grey; hyalite, a colorless glass-clear opal sometimes called Muller's Glass; geyserite, (siliceous sinter) deposited around hot springs or geysers; and diatomite or diatomaceous earth, the accumulations of diatom shells or tests. The reddish-orange color that neon emits in neon lights is widely used to make advertising signs. The triplet cut backs the colored material with a dark backing, and then has a cap of clear quartz (rock crystal) on top, which takes a high polish, and acts as a protective layer for the comparatively delicate opal.

Neon has the most intense discharge at normal voltages and currents of all the rare gases. Given the texture of opals, they can be quite difficult to polish to a reasonable lustre. In most applications it is a less expensive refrigerant than helium. The darker backing emphasizes the play of color, and results in a more attractive display than a lighter potch. Neon is the second-lightest noble gas, glows reddish-orange in a vacuum discharge tube and has over 40 times the refrigerating capacity of liquid helium and three times that of liquid hydrogen (on a per unit volume basis). An opal doublet is a thin layer of colorful material, backed by a black mineral, such as ironstone, basalt or obsidian. . The veins of opal displaying the play of color are often quite thin, and this has given rise to unusual methods of preparing the stone as a gem.

A colorless nearly inert noble gas, neon gives a distinct reddish glow when used in vacuum discharge tubes and neon lamps and is found in air in trace amounts. Potch does not show a play of color. Neon is the chemical element in the periodic table that has the symbol Ne and atomic number 10. Contrarily, opalescence is correctly applied to the milky, turbid appearance of common or potch opal. Los Alamos National Laboratory – Neon. The term opalescence is commonly and erroneously used to describe this unique and beautiful phenomenon, which is correctly termed play of color. Liquefied neon is commercially used as an economical cryogenic refrigerant. In addition microfractures may be filled with secondary silica and form thin lamellae inside the opal during solidification.

Neon and helium are used to make a type of gas laser. 444). television tubes. These ordered silica spheres produce the internal colors by causing the interference and diffraction of light passing through the microstructure of opal (Klein and Hurlbut, 1985, p. wave meter tubes. At the micro scale precious opal is composed of hexagonal or cubic closely packed silica spheres some 150 to 300 nm in diameter. lightning arrestors. Precious opal shows a variable interplay of internal colours and does have an internal structure.

high-voltage indicators. . vacuum tubes. The word opal comes from the Sanskrit upala, the Greek opallios, and the Latin opalus, meaning "precious stone.". Common opal is truely amorphous, but precious opal does have a structural element. Opal ranges from colorless through white, milky blue, gray, red, yellow, green, brown and black.

The mineraloid opal is amorphous SiO2·nH2O; hydrated silicon dioxide, the water content sometimes being as high as 20%.

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