HELIUM CAS 7440-59-7
Introduction：Basic information about HELIUM CAS 7440-59-7, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.
HELIUM Basic information
| Product Name: | HELIUM |
| Synonyms: | HELIUM;HYDROGEN AND HELIUM;HYDROGEN-HELIUM;LEAK DETECTION STANDARD LD-3;atomichelium;He;helium,compressed;Primarily commercial liquefaction plants |
| CAS: | 7440-59-7 |
| MF: | He |
| MW: | 4 |
| EINECS: | 231-168-5 |
| Product Categories: | Chemical Synthesis;Specialty Gases;Synthetic Reagents;Chemical Synthesis;Compressed and Liquefied Gases;Synthetic Reagents;refrigerants;Inorganics |
| Mol File: | 7440-59-7.mol |
HELIUM Chemical Properties
| Melting point | -272.2 °C(lit.) |
| Boiling point | -268.934 °C(lit.) |
| density | 0.1785（0℃） |
| vapor density | 0.14 (vs air) |
| solubility | slightly soluble in H2O; insoluble in ethanol |
| form | gas |
| color | colorless |
| Odor | at 100.00?%. odorless |
| Water Solubility | 8.61mL/1000g H2O (101.32kPa, 0°C) [KIR78]; Henry’s law constants, k×10?4: 9.856 (104°C), 6.739 (149.4°C), 2.524 (250.6°C), 1.796 (275.1°C) [POT78] |
| Merck | 13,4645 |
| Dielectric constant | 1.0（-269℃） |
| Stability: | Stable; extremely unreactive. |
| InChI | 1S/He |
| InChIKey | SWQJXJOGLNCZEY-UHFFFAOYSA-N |
| SMILES | [He] |
| LogP | 0.280 |
| CAS DataBase Reference | 7440-59-7(CAS DataBase Reference) |
| EPA Substance Registry System | Helium (7440-59-7) |
Safety Information
| Safety Statements | 9 |
| RIDADR | UN 1046 2.2 |
| WGK Germany | 3 |
| RTECS | MH6520000 |
| F | 4.5-31 |
| TSCA | TSCA listed |
| DOT Classification | 2.2 (Nonflammable gas) |
| HazardClass | 2.2 |
| Storage Class | 2A - Gases |
| Hazard Classifications | Press. Gas Compr. Gas |
| Hazardous Substances Data | 7440-59-7(Hazardous Substances Data) |
| Description | Helium is a colorless, odorless, and tasteless monoatomic gas withan atomic weight of 4, a density of 1.78 g per 1 at 0°C and 1 atmosphere pressure, and an aqueous solubility of 0.97 mL per 100 mL at 50°C. The Bunsen solubility coefficient (the volume, in mL, of gas at standard conditions dissolved per mL of liquid). of helium at 38°C is 0.0086 in water, and 0.015 in olive oil. After hydrogen, helium is the most abundant element in the universe; these elements are believed to represent 76 and 23 percent, respectively, of all matter in the universe. The earth’s atmosphere, however, contains only 5 ppm of helium. Mineral gases from wells contain higher concentrations and serve as the principal source for industrial production. Helium is chemically very inert; it has a weak tendency to combine with other elements such as fluorine. It is usually marketed as compressed gas, with the USP grade containing not less than 99 percent helium. The largest biological use of helium is the replacement for nitrogen in synthetic breathing gas mixtures for divers and others working under high pressure conditions. The low solubility in body fluids compared to nitrogen decreases the danger of bends on depressurizing. |
| Chemical Properties | colourless gas |
| Chemical Properties | Helium is a colorless, odorless, and tastelessgas. It is nonflammable. |
| Physical properties | Helium is a colorless, odorless, and tasteless inert gas that is noncombustible and is the leastsoluble of any gas in water and alcohol. As a gas, it diffuses well in solids. Helium’s freezingpoint is –272.2°C, and its boiling point is –268.93°C. Both temperatures are near absolutezero (–273.13°C, or –459.4°F), where all molecular and thermal motion ceases. Liquid heliumhas the lowest temperature of any known substance. Helium’s density is 0.0001785g/cm3. Helium is the only element that cannot be converted into a solid by lowering the temperature.At normal pressure it remains a liquid at near absolute zero, but if the pressure isincreased, it then turns into a solid. |
| Isotopes | There are eight isotopes of helium. Two of these are stable. They are He-3,which makes up just 0.000137% of natural helium found on Earth, and He-4, whichaccounts for 99.999863% of the natural abundance of helium on Earth. Another isotope,He-5, is an extremely rare radioisotope that decays by emitting beta particles toform lithium-6 and lithium-8. |
| Origin of Name | From the Greek word helios, meaning the “sun.” Through the processof spectrometry, it was discovered on the sun before it was found on Earth in 1868. |
| Occurrence | Helium is the 73rd most abundant element on Earth, but it is the second most abundant element in the universe, after hydrogen. Together, helium and hydrogen make up 99.9% of all the elements in the universe, but helium makes up only a small trace of the elements on Earth. Most likely, helium was the first element to be formed after hydrogen during the Big Bang formation of the universe. The theory is that hydrogen atoms combined under great heat and pressure to form helium atoms. The Earth s current helium originally came from the natural decay of radioactive elements deep in the Earth. Much of it seeps up to the surface and escapes into the atmosphere, or it mixes with natural gas deposits deep in the Earth. Like hydrogen, it is a very light gas that escapes through cracks in the Earth s crust and sooner or later escapes from Earth s gravity into the atmosphere. Helium can be obtained from the atmosphere by lowering the temperature of air until it liquefies. All the other gases in air will turn to a liquid except helium, because it has the lowest boiling point. Since helium, at this stage of cooling, will be the only vapor left, it can be removed as a pure gas. It is commercially more profitable to produce helium by separating it from a mix of natural underground gases, where its concentration is greater that in the atmosphere. Raw natural gas is a mixture of methane, nitrogen, and helium, with traces of other gases. The nitrogen and helium are separated from the methane, which is used as a fuel. This separation is accomplished by fractional distillation wherein the temperature is reduced and the gases are liquefied. As the temperature is reduced, methane is liquefied first, then nitrogen, leaving helium to be collected and sold commercially. Helium is then purified to 99.995%. Most of the world s supply of helium comes from the United States. |
| Characteristics | When a second proton and two neutrons are added to a hydrogen nucleus, a helium atomcan form after it collects two electrons. Helium is the most inert of all the noble group 18gases. It is so inactive that it does not even combine with itself. As a gas, helium remains asa single atom. The nuclei of helium are called alpha particles, each of which has a charge of+2 and an atomic mass of 4. No stable compound of helium has ever been found. However, it is possible for an atom ofhydrogen to combine with helium (and other light noble elements) under special conditionsto form HeH+, an unstable ion. Helium is not plentiful on Earth and is only the sixth most abundant gas in the atmosphere.It does not accumulate in the atmosphere because it is lighter than air. Some amountof helium continually escapes into space from the outer atmosphere of the Earth. Liquid helium exhibits some unusual characteristics when supercooled. First, it is the onlyelement that will not turn into a solid by just using pressure. Heat must be removed as thepressure is increased, but helium will freeze at –272.2°C, which is the lowest temperature scientistshave ever achieved. Second, it is an excellent conductor of heat. As a supercold liquid,it will move toward heat—even flow up the sides and over the top of a container. |
| History | valence usually 0. Evidence of the existence of helium was first obtained by Janssen during the solar eclipse of 1868 when he detected a new line in the solar spectrum; Lockyer and Frankland suggested the name helium for the new element; in 1895, Ramsay discovered helium in the uranium mineral cleveite, and it was independently discovered in cleveite by the Swedish chemists Cleve and Langlet about the same time. Rutherford and Royds in 1907 demonstrated that α particles are helium nuclei. Except for hydrogen, helium is the most abundant element found throughout the universe. Helium is extracted from natural gas; all natural gas contains at least trace quantities of helium. It has been detected spectroscopically in great abundance, especially in the hotter stars, and it is an important component in both the proton–proton reaction and the carbon cycle, which account for the energy of the sun and stars. The fusion of hydrogen into helium provides the energy of the hydrogen bomb. The helium content of the atmosphere is about 1 part in 200,000. It is present in various radioactive minerals as a decay product. Much of the world’s supply of helium is obtained from wells in Texas, Colorado, and Kansas. The only other known helium extraction plants, outside the United States, in 1999 were in Poland, Russia, China, Algeria, and India. The cost of helium has fallen from $2500/ft3 in 1915 to about 2.5￠/cu.ft. (.028 cu meters) in 1999. Helium has the lowest melting point of any element and has found wide use in cryogenic research, as its boiling point is close to absolute zero. Its use in the study of superconductivity is vital. Using liquid helium, Kurti and co-workers, and others, have succeeded in obtaining temperatures of a few microkelvins by the adiabatic demagnetization of copper nuclei, starting from about 0.01 K. Liquid helium (He4) exists in two forms: He4I and He4II, with a sharp transition point at 2.174 K (3.83 cm Hg). He4I (above this temperature) is a normal liquid, but He4II (below it) is unlike any other known substance. It expands on cooling; its conductivity for heat is enormous; and neither its heat conduction nor viscosity obeys normal rules. It has other peculiar properties. Helium is the only liquid that cannot be solidified by lowering the temperature. It remains liquid down to absolute zero at ordinary pressures, but it can readily be solidified by increasingthe pressure. Solid 3He and 4He are unusual in that both can readily be changed in volume by more than 30% by application of pressure. The specific heat of helium gas is unusually high. The density of helium vapor at the normal boiling point is also very high, with the vapor expanding greatly when heated to room temperature. Containers filled with helium gas at 5 to 10 K should be treated as though they contained liquid helium due to the large increase in pressure resulting from warming the gas to room temperature. While helium normally has a 0 valence, it seems to have a weak tendency to combine with certain other elements. Means of preparing helium diflouride have been studied, and species such as HeNe and the molecular ions He+ and He++ have been investigated. Helium is widely used as an inert gas shield for arc welding; as a protective gas in growing silicon and germanium crystals, and in titanium and zirconium production; as a cooling medium for nuclear reactors, and as a gas for supersonic wind tunnels. A mixture of helium and oxygen is used as an artificial atmosphere for divers and others working under pressure. Different ratios of He/O2 are used for different depths at which the diver is operating. Helium is extensively used for filling balloons as it is a much safer gas than hydrogen. One of the recent largest uses for helium has been for pressurizing liquid fuel rockets. A Saturn booster such as used on the Apollo lunar missions required about 13 million ft3 of helium for a firing, plus more for checkouts. Liquid helium’s use in magnetic resonance imaging (MRI) continues to increase as the medical profession accepts and develops new uses for the equipment. This equipment is providing accurate diagnoses of problems where exploratory surgery has previously been required to determine problems. Another medical application that is being developed uses MRI to determine by blood analysis whether a patient has any form of cancer. Lifting gas applications are increasing. Various companies in addition to Goodyear, are now using “blimps” for advertising. The Navy and the Air Force are investigating the use of airships to provide early warning systems to detect low-flying cruise missiles. The Drug Enforcement Agency has used radar-equipped blimps to detect drug smugglers along the southern border of the U.S. In addition, NASA is currently using helium-filled balloons to sample the atmosphere in Antarctica to determine what is depleting the ozone layer that protects Earth from harmful U.V. radiation. Research on and development of materials which become superconductive at temperatures well above the boiling point of helium could have a major impact on the demand for helium. Less costly refrigerants having boiling points considerably higher could replace the present need to cool such superconductive materials to the boiling point of helium. Natural helium contains two stable isotopes 3He and 4He. 3He is present in very small quantities. Six other isotopes of helium are now recognized. |
| Uses | Helium has many uses. As an inert gas, it is used as the atmosphere in which to “grow” silicon crystals (computerchips). As a lifting gas, it is used to inflate weather balloons and lighter-than-air ships (blimps)similar to the ones seen taking TV pictures above football games. Even though helium has lesslifting power than hydrogen, it is used for all lighter-than-air ships because it is noncombustibleand thus safer than hydrogen. In addition to blimps, toy balloons are filled with helium. In arc welding, it is used as an inert gas shield that releases great heat for very long andheavy welds. Helium prevents oxidation of the metal being welded, thus preventing burningand corrosion of the metal. This is one of the major uses of helium. Helium is used for low-temperature research (–272.2°C or –434°F). It has become importantas a coolant for superconducting electrical systems that, when cooled, offer little resistance to theelectrons passing through a conductor (wire or magnet). When the electrons are “stripped” fromthe helium atom, a positive He++ ion results. The positive helium ions (nuclei) occur in bothnatural and man-made radioactive emissions and are referred to as alpha particles. Helium ions(alpha particles) are used in high-energy physics to study the nature of matter. In gas discharge lasers, helium transfers the energy to the laser gas such as carbon dioxideor another inert gas;in mixtures with neon and argon for electronic tubes and “neon” signs.. As an inert gas with heat-transfer capability, helium is used in gas-cooled nuclear powerreactors, which operate at a higher efficiency than liquid-cooled nuclear reactors. Theworld’s largest particle accelerators use liquid helium to cool their superconducting magnets.Astronomers use liquid helium to cool their detecting instruments. If this equipment is keptcool, the “thermal noise” produced at higher temperatures is reduced. |
| Uses | Gases, diluent. |
| Uses | Helium is used as an inert gas shield in arcwelding, as a lifting gas for lighter-than-air aircraft,and as a gaseous cooling medium in nuclearreactors. It is also used to provide a protectiveatmosphere for growing germanium andsilicon crystals for transistors, to provide a protectiveatmosphere in the production of suchreactive metals as titanium and zirconium, to fillcold-weather fluorescent lamps, to trace leaks inrefrigeration and other closed systems, and to fill neutron and gas thermometers. Its thermalconductivity makes it an important gas for lasersand fiber optic production. It is used extensivelyin chromatography due to its inertness and highthermal conductivity. It is used in cryogenicresearch such as for superconductivity. In mixtureswith oxygen, it has medical and divingapplications. Radioactive mixtures of heliumwith krypton are available to users licensed bythe Nuclear Regulatory Commission. NASAuses helium for purging and pressurizing theliquid hydrogen tanks of spacecraft because it isthe only element that remains a gas in the extremecold necessary to maintain the liquid hydrogenfuel used in many rockets and the SpaceShuttle. Liquid helium is used for cooling superconductivemagnets, used in magnetic resonanceimaging, and in magnetic separation. |
| Production Methods | Helium is produced mostly by extraction from natural gas. The process involves cooling the stream of natural gas at sufficient low temperatures and high pressures to liquefy and separate all hydrocarbons, nitrogen and other gases from gaseous helium. The ‘crude’ helium gas may be purified further by repeated liquefaction of methane, nitrogen and other impurities under pressure. Trace hydrocarbons may be removed by adsorption on activated charcoal at liquid nitrogen temperature. Water may be removed by drying over a dehydrating agent such as bauxite. Carbon dioxide may be removed by passing helium through a scrubbing solution containing monoethanolamine-ethylene glycol or similar substances. Trace hydrogen may be removed from helium by converting it into water by mixing with oxygen and passing the mix over a palladium catalyst. Final purification may be achieved by adsorbing remaining trace contaminants over activated charcoal at liquid nitrogen temperature. Alternatively, helium may be separated from natural gas by diffusion through permeable barriers, such as high silica glass or semipermeable membranes. The gas is supplied commercially in steel cylinders or tanks. The United States is the largest producer of helium in the world. |
| Definition | Noble element of atomic number 2, first elementin the noble gas group of the periodic table, aw4.00260, valence of 0. Helium nuclei are alpha particles. Most important isotope is helium-3. |
| Definition | A colorlessmonatomic gas; the first member of therare gases (group 18 of the periodic table).Helium has the electronic configuration1s2 and consists of a nucleus of two protonsand two neutrons (equivalent to an α-particle) with two extra-nuclear electrons.It has an extremely high ionization potentialand is completely resistant to chemicalattack of any sort. The gas accounts foronly 5.2 × 10-4% of the atmosphere; up to7% occurs in some natural gas deposits.Helium is the second most abundant elementin the universe, the primary processon the Sun being nuclear fusion of hydrogento give helium. Helium is recovered commercially fromnatural gas in both the USA and countriesof the former USSR and it also forms partof ammonia plant tail gas if natural gas isused as a feedstock. Its applications are infields in which inertness is required andwhere the cheaper alternatives, such asnitrogen, are too reactive; for example,high-temperature metallurgy, powder technology,and as a coolant in nuclear reactors.Helium is also favoured over nitrogenfor diluting oxygen for deep-sea diving(lower solubility in blood) and as a pressurizerfor liquefied gas fuels in rockets(total inertness). It is also used as an idealgas for balloons (no fire risk) and for lowtemperaturephysics research. Helium is unusual in that it is the onlyknown substance for which there is notriple point (i.e., no combination of pressureand temperature at which all threephases can co-exist). This is because the interatomicforces, which normally participatein the formation of solids, are so weakthat they are of the same order as the zeropointenergy. At 2.2 K helium undergoes atransition from liquid helium I to liquidhelium II, the latter being a true liquid butexhibiting superconductivity and an immeasurablylow viscosity (superfluidity). The low viscosity allows the liquid tospread in layers a few atoms thick, describedby some as ‘flowing uphill’. Helium also has an isotope. 3He isformed in nuclear reactions and by decayof tritium. This also undergoes a phasechange at temperatures close to absolutezero. Symbol: He; m.p. 0.95 K (pressure);b.p. 4.216 K; d. 0.1785 kg m-3 (0°C); p.n.2; r.a.m. 4.002602. |
| Definition | helium: Symbol He. A colourlessodourless gaseous nonmetallic elementbelonging to group 18 of theperiodic table ; a.n.2; r.a.m. 4.0026; d. 0.178 g dm–3; m.p.–272.2°C (at 20 atm.); b.p. –268.93°C.The element has the lowest boilingpoint of all substances and can be solidifiedonly under pressure. Naturalhelium is mostly helium–4, with asmall amount of helium–3. There arealso two short-lived radioactive isotopes:helium–5 and –6. It occurs inores of uranium and thorium and insome natural-gas deposits. It has a varietyof uses, including the provisionof inert atmospheres for welding andsemiconductor manufacture, as a refrigerantfor superconductors, and asa diluent in breathing apparatus. It isalso used in filling balloons. Chemicallyit is totally inert and has noknown compounds. It was discoveredin the solar spectrum in 1868 byJoseph Lockyer (1836–1920). |
| General Description | A colorless, odorless, noncombustible gas. Can asphyxiate. Inhalation causes the voice to become squeaky (Mickey Mouse voice). Exposure of the container to prolonged heat or fire can cause HELIUM to rupture violently and rocket. If liquefied, contact of the very cold liquid with water causes violent boiling. Pressures may build to dangerous levels if the liquid contacts water in a closed container. Used in arc welding, to trace leaks in refrigeration and other closed systems and as a lifting gas for lighter-than-air aircraft. |
| Reactivity Profile | Chemically inert. These substances undergo no chemical reactions under any known circumstances. They are nonflammable, noncombustible and nontoxic. They can asphyxiate. |
| Hazard | Being inert, the noble gases are nontoxic. However, they can act as asphyxiant gases thatcan kill because of oxygen deprivations. A possible hazard is when He++ nuclei, as alpha particles, are accelerated to high speeds andbombard a target. Alpha particles can be stopped by several inches of air or a piece of cardboard.As high-energy, charged particles generated from man-made or natural radioactivity,alpha particles can cause damage, but they are not as damaging to our bodies as are very shortwavelength gamma rays, which can only be stopped by lead shielding. |
| Health Hazard | Vapors may cause dizziness or asphyxiation without warning. Vapors from liquefied gas are initially heavier than air and spread along ground. |
| Fire Hazard | Non-flammable gases. Containers may explode when heated. Ruptured cylinders may rocket. |
| Industrial uses | Helium is a colorless, odorless, elementary gas,He, with a specific gravity of 0.1368, liquefyingat –268.9°C, freezing at –272.2°C. It has avalency of zero and forms no electron-bondedcompounds. It has the highest ionization potentialof any element. The lifting power of heliumis only 92% that of hydrogen, but it is preferredfor balloons because it is inert and nonflammable,and is used in weather balloons. It is alsoused instead of air to inflate large tires for aircraftto save weight. Because of its low density,it is also used for diluting oxygen in the treatmentof respiratory diseases. Its heat conductivityis about six times that of air, and it is usedas a shielding gas in welding, and in vacuumtube and electric lamps. Because of its inertnesshelium can also be used to hold free chemicalradicals, which, when released, give highenergy and thrust for missile propulsion. Whenan electric current is passed through helium itgives a pinkish-violet light, and is thus used inadvertising signs. Helium can be obtained fromatmospheric nitrogen, but comes chiefly fromnatural gas. |
| Materials Uses | Gaseous helium is noncorrosive and inert, andmay consequently be contained in systems constructed of any common metals and designed tosafely withstand the pressures involved. At thetemperature of liquid helium, ordinary carbonsteels and most alloy steels lose their ductilityand are considered unsafe for liquid heliumservice. Satisfactory materials for use with liquidhelium include Type 18-8 stainless steel andother austenitic nickel-chromium alloys, copper,Monel, brass, and aluminum. |
| Potential Exposure | It is used in weather balloons and inwelding gases. Liquid helium is used as a closed systemcooling agent. |
| Physiological effects | Helium is nontoxic and inert. It can act as asimple asphyxiant by diluting the concentrationof oxygen in air below levels necessary to supportlife. Inhalation in excessive concentrationscan result in dizziness, nausea, vomiting, loss ofconsciousness, and death. Death may resultfrom errors in judgment, confusion, or loss ofconsciousness, which prevent self-rescue. Atlow-oxygen concentrations, unconsciousnessand death may occur in seconds without warning. |
| First aid | If frostbite has occurred, seek medical attentionimmediately; do not rub the affected areas or flushthem with water. In order to prevent further tissue damage, donot attempt to remove frozen clothing from frostbittenareas. If frostbite has NOT occurred, immediately and thor-oughly wash contaminated skin with soap and water. Seekmedical attention promptly. Breathing: Remove the personfrom exposure. Begin rescue breathing (using universal pre-cautions，including resuscitation mask) if breathing hasstoppedand CPR if heart action has stopped. Transferpromptly to a medical facility. |
| storage | Gaseous helium is commonly stored in highpressure cylinders, hydril tubes, or tube trailers.Liquid helium is commonly stored at the consumersite in cryogenic liquid cylinders, portablecustomer stations, and specially designedinsulated tanks. To minimize helium transfer losses, the shipping container for liquid heliumis normally used for storage. |
| Shipping | UN1046 Helium, compressed, Hazard Class: 2.2;Labels: 2.2-Nonflammable compressed gas; UN1963Helium, refrigerated liquid (cryogenic liquid), HazardClass: 2.2; Labels: 2.2-Nonflammable compressed gas. |
| Purification Methods | Dry the gas by passing it through a column of Linde 5A molecular sieves and CaSO4, then through an activated-charcoal trap cooled in liquid N2, to adsorb N2, argon, xenon and krypton. Also pass it over CuO pellets at 300o to remove hydrogen and hydrocarbons, over Ca chips at 600o to remove oxygen, and then over titanium chips at 700o to remove N2 [Arnold & Smith J Chem Soc, Faraday Trans 2 77 861 1981]. Its solubility in 100mL of H2O is 0.94mL at 25o, 1.05mL at 50o and 1.21 at 75o. |
| Waste Disposal | Return refillable compressedgas cylinders to supplier. |
| GRADES AVAILABLE | CGA G-9.1, Commodity Specificationfor Helium, presents the componentmaxima, in parts per million (v/v) unless otherwiseshown, for specific grades of helium, alsoknown as quality verification levels (QVLs) [I].A blank indicates no maximum limiting characteristic.The absence of a value in a listedQVL does not mean to imply that the limitingcharacteristic is or is not present, but merelyindicates that the test is not required for compliancewith the specification. |
HELIUM Preparation Products And Raw materials
| Raw materials | Ammonia |
| Preparation Products | NEON |
