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Neon, the name of which is derived from the Greek word neos, "new," is present in some minerals, but its only commercial source is the atmosphere, of which it comprises 18 parts per 1,000,000 by volume. Because its boiling point is -246° C, neon remains, along with helium and hydrogen, in the small fraction of air that resists liquefaction upon cooling to -196° C. Neon is isolated from this cold, gaseous mixture by bringing it into contact with activated charcoal, which adsorbs the neon and hydrogen; removal of hydrogen is effected by adding enough oxygen to convert it all to water, which, along with any surplus oxygen, condenses upon cooling.

Neon was the first element shown to consist of more than one stable isotope. In 1913 application of the technique of mass spectrometry revealed the existence of neon-20 and neon-22, which comprise 90.92 and 8.82 percent, respectively, of the naturally occurring mixture. The third stable isotope, neon-21, which makes up 0.26 percent of natural neon, was detected later. Five radioactive isotopes of neon also have been identified.

(Ne), chemical element, inert gas of Group 0 (noble gases) of the periodic table, used in electric signs and fluorescent lamps. Colourless, odourless, tasteless, and lighter than air, neon gas occurs in minute quantities in the Earth's atmosphere and trapped within the rocks of the Earth's crust. Though neon is about 3 1/2 times as plentiful as helium in the atmosphere, dry air contains only 0.0018 percent neon by volume. This element is more abundant in the cosmos than on Earth. Neon liquefies at -246.048° C (-411° F) and freezes at a temperature only 2 1/25 lower. When under low pressure, it emits a bright orange-red light if an electrical current is pass-ed through it. This property is utilized in neon signs (which first became familiar in the 1920s), in some fluorescent and gaseous conduction lamps, and in high-voltage testers.

Neon is separated from helium by selective adsorption on activated charcoal at low temperatures.
Processing 88,000 pounds of liquid air will produce one pound of neon.

No stable chemical compounds of neon have been observed. Molecules of the element consist of single atoms. Natural neon is a mixture of three stable isotopes: neon-20 (90.92 percent); neon-21 (0.26 percent); and neon-22 (8.82 percent).