Neon

BeschreibungIn 1898, Dr William Ramsay and Morris M. Travers, a Scottish scientist and a British scientist, respectively, discovered neon as a condensation product in liquefied air, as in a process similar to that used to collect neon today. Neon’s use in lighting evolved from discoveries that gases under low pressure conduct electricity. When some flowing electrons collide with residual gas in an evacuated glass tube, the resulting ions emit light as they return to their nonexcited state. The color of the light depends on the residual gas; neon gas produces a red color and argon, another inert gas often used in tubes (which are frequently and incorrectly called neon lights), produces a blue color. These two basic colors are often modified into many different hues by the addition of such elements as mercury and cadmium. The neon found on the Earth is considered to be primordial in origin. Most of the neon is sequestered in the Earth’s rocks or dissolved in water, with small amounts escaping into the atmosphere during geologic weathering. The escaped gas is slowly lost into space faster than it is replenished. Consequently, neon constitutes only a small part (0.0018%) of the Earth’s atmosphere, although this element is estimated to be the fourth most abundant in the universe.

OccurrenceNeon is the fourth most abundant element in the universe, but it makes up only 18.18ppm of the Earth’s atmosphere. It is the 82nd most abundant element on Earth. Neon is believed to be produced by radioactive decay deep in the Earth. As it rises to thesurface, it escapes into the atmosphere and is soon dissipated. Some neon is found mixed withnatural gas and several minerals. Neon is produced as a secondary product of the fractional distillation of liquid nitrogenand oxygen. Air is liquefied, and as it warms, nitrogen and oxygen boil off, leaving behindseveral other colder gases, including about 75% neon, which is then passed through activatedcharcoal to remove hydrogen and other gases.

HistoryDiscovered 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. Natural neon is a mixture of three isotopes. Fourteen 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 optical and mass spectrometric studies: Ne+, (NeAr)+, (NeH)+, and (HeNe+). Neon also forms an unstable hydrate. In a vacuum discharge tube, neon glows reddish 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 common neon advertising signs, which accounts for its largest use. It is also used to make 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. It has over 40 times more refrigerating capacity per unit volume than liquid helium and more than three times that of 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).