"Buffer gas A buffer gas is an inert or nonflammable gas. In the Earth's atmosphere, nitrogen acts as a buffer gas. A buffer gas adds pressure to a system and controls the speed of combustion with any oxygen present. Any inert gas such as helium, neon, or argon will serve as a buffer gas. Buffer gases are commonly used in many applications from high pressure discharge lamps to reduce line width of microwave transitions in alkali atoms. A buffer gas usually consists of atomically inert gases such as helium, argon, and nitrogen which are the primary gases used. Krypton, neon,"
"carbon dioxide. (Listed as many different names depending on the gas supplier). In underwater diving an inert gas is a component of the breathing mixture which is not metabolically active, and serves to dilute the gas mixture. The inert gas may have effects on the diver, but these are thought to be mostly physical effects, such as tissue damage caused by bubbles in decompression sickness. The most common inert gas used in breathing gas for commercial diving is helium. Inert gas An inert gas/noble gas is a gas which does not undergo chemical reactions under a set of given conditions."
"water molecules. Ions, such as , and excited-state complexes, such as ArF, have been demonstrated. Theoretical calculation predicts several more argon compounds that should be stable but have not yet been synthesized. ""Argon"" (Greek , neuter singular form of meaning ""lazy"" or ""inactive""), is named in reference to its chemical inactivity. This chemical property of this first noble gas to be discovered impressed the namers. An unreactive gas was suspected to be a component of air by Henry Cavendish in 1785. Argon was first isolated from air in 1894 by Lord Rayleigh and Sir William Ramsay at University College London"
"Inert gas An inert gas/noble gas is a gas which does not undergo chemical reactions under a set of given conditions. The noble gases often do not react with many substances, and were historically referred to as the inert gases. Inert gases are used generally to avoid unwanted chemical reactions degrading a sample. These undesirable chemical reactions are often oxidation and hydrolysis reactions with the oxygen and moisture in air. The term ""inert gas"" is context-dependent because several of the noble gases can be made to react under certain conditions. Purified argon and nitrogen gases are most commonly used as"
"inert gases due to their high natural abundance (78.2% N, 1% Ar in air) and low relative cost. Unlike noble gases, an inert gas is not necessarily elemental and is often a compound gas. Like the noble gases the tendency for non-reactivity is due to the valence, the outermost electron shell, being complete in all the inert gases. This is a tendency, not a rule, as noble gases and other ""inert"" gases can react to form compounds. The inert gases are obtained by fractional distillation of air, with the exception of helium which is separated from a few natural gas"
"in chemical compounds was lower than that of nitrogen found in the atmosphere. He ascribed this discrepancy to a light gas included in chemical compounds of nitrogen, while Ramsay suspected a hitherto undiscovered heavy gas in atmospheric nitrogen. Using two different methods to remove all known gases from air, Ramsay and Lord Rayleigh were able to announce in 1894 that they had found a monatomic, chemically inert gaseous element that constituted nearly 1 percent of the atmosphere; they named it argon. The following year, Ramsay liberated another inert gas from a mineral called cleveite; this proved to be helium, previously"
"In food packaging, inert gases are used as a passive preservative, in contrast to active preservatives like sodium benzoate (an antimicrobial) or BHT (an antioxidant). Historical documents may also be stored under an inert gas to avoid degradation. For example, the original documents of the U.S. Constitution is stored under humidified argon. Helium was previously used, but it was less suitable because it diffuses out of the case more quickly than argon. Inert gases are often used in the chemical industry. In a chemical manufacturing plant, reactions can be conducted under inert gas to minimize fire hazards or unwanted reactions."
"Krypton Krypton (from ""the hidden one"") is a chemical element with symbol Kr and atomic number 36. It is a member of group 18 (noble gases) elements. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. With rare exceptions, krypton is chemically inert. Krypton, like the other noble gases, is used in lighting and photography. Krypton light has many spectral lines, and krypton plasma is useful in bright, high-powered gas lasers (krypton ion and excimer lasers), each of which resonates and amplifies a single"
"lines which Lockyer had observed: helium. Prior to this, Ramsay had already isolated a new gas from the atmosphere; argon, with an atomic weight of 40. A problem now arose – Mendeleev had not left any gaps which were suitable for either of these two new elements, which led Ramsay to conclude an entire group was missing from the periodic table – only two of whose members were now known to exist, helium and argon. Ramsey successfully discovered all the other stable elements in the group which he named neon (Greek for new), krypton (Greek for hidden) and xenon (Greek"
"Neon Neon is a chemical element with symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypton and xenon) in 1898 as one of the three residual rare inert elements remaining in dry air, after nitrogen, oxygen, argon and carbon dioxide were removed. Neon was the second of these three rare gases to be discovered and was immediately recognized as a new element from its bright red emission spectrum. The name neon is derived from"
"Inert gas asphyxiation Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen, rather than atmospheric air (which is largely composed of nitrogen and oxygen). Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, helium, nitrogen and methane. The term ""physiologically inert"" is used to indicate a gas which has no toxic or anesthetic properties and does not act upon the heart or hemoglobin. Instead, the gas acts as a simple diluent to reduce oxygen"
"the Greek word, , neuter singular form of (""neos""), meaning new. Neon is chemically inert, and no uncharged neon compounds are known. The compounds of neon currently known include ionic molecules, molecules held together by van der Waals forces and clathrates. During cosmic nucleogenesis of the elements, large amounts of neon are built up from the alpha-capture fusion process in stars. Although neon is a very common element in the universe and solar system (it is fifth in cosmic abundance after hydrogen, helium, oxygen and carbon), it is rare on Earth. It composes about 18.2 ppm of air by volume"
"Shielding gas Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding (GMAW and GTAW, more popularly known as MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas), respectively). Their purpose is to protect the weld area from oxygen, and water vapour. Depending on the materials being welded, these atmospheric gases can reduce the quality of the weld or make the welding more difficult. Other arc welding processes use alternative methods of protecting the weld from the atmosphere as well – shielded metal arc"
"solvent. Diffusion is faster in smaller, lighter molecules of which helium is the extreme example. Diffusivity of helium is 2.65 times faster than nitrogen. The concentration gradient, can be used as a model for the driving mechanism of diffusion. In this context, inert gas refers to a gas which is not metabolically active. Atmospheric nitrogen (N) is the most common example, and helium (He) is the other inert gas commonly used in breathing mixtures for divers. Atmospheric nitrogen has a partial pressure of approximately 0.78 bar at sea level. Air in the alveoli of the lungs is diluted by saturated"
"to be retained. Neon, argon, krypton, and xenon also form clathrate hydrates, where the noble gas is trapped in ice. Noble gases can form endohedral fullerene compounds, in which the noble gas atom is trapped inside a fullerene molecule. In 1993, it was discovered that when , a spherical molecule consisting of 60 carbon atoms, is exposed to noble gases at high pressure, complexes such as can be formed (the ""@"" notation indicates He is contained inside but not covalently bound to it). As of 2008, endohedral complexes with helium, neon, argon, krypton, and xenon have been obtained. These compounds"
"Inerting (gas) In fire and explosion prevention engineering, inerting refers to the introduction of an inert (non-combustible) gas into a closed system (e.g. a container or a process vessel) to make the atmosphere oxygen deficient and non-ignitable. Inerting relies on the principle that a combustible (or flammable) gas is able to undergo combustion (explode) only if mixed with air in the right proportions. The flammability limits of the gas define those proportions, i.e. the ignitable range. In combustion engineering terms, the admission of inert gas can be said to dilute the oxygen below the limiting oxygen concentration. Inerting differs from"
"an inert gas provides a higher degree of safety however, because the practice ensures that an ignitable mixture never forms. Purging can therefore be said to rely on primary prevention, reducing the possibility of an explosion, whereas control of sources of ignition relies on secondary prevention, reducing the probability of an explosion. Primary prevention is also known as inherent safety. The purge gas is inert, i.e. by definition non-combustible, or more precisely, ""non-reactive"". The most common purge gases commercially available in large quantities are nitrogen and carbon dioxide. Other inert gases, e.g. argon or helium may be used. Nitrogen and"
"inert gas. In 1913, Frank E. Elmore developed a flotation process to recover molybdenite from ores; flotation remains the primary isolation process. During the first World War, demand for molybdenum spiked; it was used both in armor plating and as a substitute for tungsten in high speed steels. Some British tanks were protected by 75 mm (3 in) manganese steel plating, but this proved to be ineffective. The manganese steel plates were replaced with 25 mm (1 in) molybdenum-steel plating allowing for higher speed, greater maneuverability, and better protection. After the war, demand plummeted until metallurgical advances allowed extensive development"
"outside of the context of electron configurations: When the noble gases (then called ""inert gases"") were first discovered around 1900, they were known as ""group 0"", reflecting no chemical reactivity of these elements known at that point, and helium was placed on the top of that group, as it did share the extreme chemical inertness seen throughout the group. As the group changed its formal number, many authors continued to assign helium directly above neon, in group 18; one of the examples of such placing is the current IUPAC table. Hydrogen's chemical properties are not very close to those of"
"elements. The term ""inert"" may also be applied in a relative sense. For example, molecular nitrogen is an inert gas under ordinary conditions, existing as diatomic molecules, . The presence of a strong triple covalent bond in the molecule renders it unreactive under normal circumstances. Nevertheless, nitrogen gas does react with the alkali metal lithium to form compound lithium nitride (LiN), even under ordinary conditions. Under high pressures and temperatures and with the right catalysts, nitrogen becomes more reactive; the Haber process uses such conditions to produce ammonia from atmospheric nitrogen . Inert atmospheres consisting of gases such as argon,"
"a short conversation he and Ramsay decided to investigate this. In August Ramsay told Rayleigh he had isolated a new, heavy component of air, which did not appear to have any chemical reactivity. He named this inert gas ""argon"", from the Greek word meaning ""lazy"". In the following years, working with Morris Travers, he discovered neon, krypton, and xenon. He also isolated helium, which had only been observed in the spectrum of the sun, and had not previously found on earth. In 1910 he isolated and characterized radon. During 1893-1902 Ramsay also collaborated with Emily Aston, a British chemist, in"
"Noble gas The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). These elements are all nonmetals. Oganesson (Og) is variously predicted to be a noble gas as well or to break the trend due to relativistic effects; its chemistry has not yet been investigated. For the first six"
"was the heaviest known gas. and wrote that ""L'expression de l'émanation du radium est fort incommode"", (the expression 'radium emanation' is very awkward) and suggested the new name niton (Nt) (from the Latin ""nitens"" meaning ""shining"") to emphasize the radioluminescence property, and in 1912 it was accepted by the International Commission for Atomic Weights. In 1923, the International Committee for Chemical Elements and International Union of Pure and Applied Chemistry (IUPAC) chose among the names radon (Rn), thoron (Tn), and actinon (An). Later, when isotopes were numbered instead of named, the element took the name of the most stable isotope,"
"will diffuse from regions of higher concentration (partial pressure) to regions of lower concentration, and the rate of diffusion is proportional to the rate of change of the concentration. Tissues in which an inert gas is more soluble will eventually develop a higher dissolved gas content than tissues where the gas is less soluble. In this context, inert gas refers to a gas which is not metabolically active. Atmospheric nitrogen (N) is the most common example, and helium (He) is the other inert gas commonly used in breathing mixtures for divers. Atmospheric nitrogen has a partial pressure of approximately 0.78"
"In gas tungsten arc welding (GTAW), inert gases are used to shield the tungsten from contamination. It also shields the fluid metal (created from the arc) from the reactive gases in air which can cause porosity in the solidified weld puddle. Inert gases are also used in gas metal arc welding (GMAW) for welding non-ferrous metals. Some gases which are not usually considered inert but which behave like inert gases in all the circumstances likely to be encountered in some use can often be used as a substitute for an inert gas. This is useful when an appropriate pseudo-inert gas"
"Greek verb ""πνίγειν"" (""pnígein""), to ""choke"" or ""stifle"", which is a property of molecular nitrogen in the absence of oxygen; it can also be used as a mnemonic for the two most common members, P and N. The name pentels (from Greek ""πέντε"", ""pénte"", five) was also used for this group at one time, stemming from the earlier group naming convention (Group V). Pnictide compounds tend to be exotic. Various properties that some pnictides have include being diamagnetic and paramagnetic at room temperature, being transparent, and generating electricity when heated. Other pnictides include the ternary rare-earth main-group variety of pnictides."
"for example, hydrogen (""water-producing""), oxygen (""acid-producing""), nitrogen (""soda-producing""), bromine (""stink""), and argon (""no reaction"") were based on Greek roots, while the names of iodine and chlorine were derived from the Greek words for their characteristic colors. Indium, rubidium, and thallium were similarly named for the colors of particular lines in their emission spectra. Iridium, which forms compounds of many different colors, takes its name from ""iris"", the Latin for ""rainbow"". The noble gases have all been named for their origin or properties. Helium comes from the Greek ""helios"", meaning ""sun"" because it was first detected as a line in the"
"sub-Poissonian, as expected for a Fermi gas. Tonks–Girardeau gas In physics, a Tonks–Girardeau gas is a Bose gas in which the repulsive interactions between bosonic particles confined to one dimension dominate the physics of the system. It is named after physicists Marvin D. Girardeau and Lewi Tonks. Strictly speaking this is not a Bose–Einstein condensate as it does not demonstrate any of the characteristics, such as off diagonal long range order or a unitary two body correlation function, even in a thermodynamic limit and as such cannot be described by a macroscopically occupied orbital (order parameter) in the Gross Pitaevskii"
"Its name derives from the Greek roots ὀξύς ""oxys"", ""acid"", literally ""sharp"", referring to the sour taste of acids and -γενής ""-genes"", ""producer"", literally ""begetter"", because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work ""Pneumatica"", Philo observed that inverting a vessel over a burning candle and surrounding the vessel's neck with water resulted in some water rising into the neck. Philo"
"Argon compounds Argon compounds, the chemical compounds that contain the element argon, are rarely encountered due to the inertness of the argon atom. However, compounds of argon have been detected in inert gas matrix isolation, cold gases, and plasmas, and molecular ions containing argon have been made and also detected in space. One solid interstitial compound of argon, ArC is stable at room temperature. ArC was discovered by CSIRO. Argon ionises at 15.76 eV, which is higher than hydrogen, but lower than helium, neon or fluorine. Molecules containing argon can be van der Waals molecules held together very weakly by"
"column of the periodic table, also known as group 0 or group 18. Noble gases are also called as aerogens but this nomenclature of the group is not officially accepted by the IUPAC. All of the noble gases have full outer shells with eight electrons. However, at the top of the noble gases is helium, with a shell that is full with only two electrons. The fact that their outer shells are full means they rarely react with other elements, which led to their original title of ""inert"". Because of their chemical properties, these gases are also used in the"
"Endothermic gas Endothermic gas is a gas that inhibits or reverses oxidation on the surfaces it is in contact with. This gas is the product of incomplete combustion in a controlled environment. An example is hydrogen gas (H), nitrogen gas (N), and carbon monoxide (CO). The hydrogen and carbon monoxide are reducing agents, so they work together to shield surfaces from oxidation. Endothermic gas is often used as a carrier gas for gas carburizing and carbonitriding. An endothermic gas generator could be used to supply heat to form an endothermic reaction. Synthesised in the catalytic retort(s) of endothermic generators, the"
"the Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in the Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in supernovas. The name ""argon"" is derived from the Greek word , neuter singular form of meaning ""lazy"" or ""inactive"", as a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83.8058 K is"