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Pyrophoricity

 
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Pyrophoricity
 
 
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A pyrophoric substance (from Greek purophoros, "fire-bearing") will ignite spontaneously; that is, its autoignition temperature
Autoignition temperature

The autoignition temperature or kindling point of a substance is the lowest temperature at which it will Spontaneous combustion in a normal atmosphere without an external source of ignition, such as a flame or spark....
 is below room temperature
Room temperature

Room temperature is a common term to denote a certain temperature within enclosed space at which humans are accustomed.Room temperature is thus often indicated by general human comfort, with the common range of 10celsius to 23?C , though climate may acclimatize people to higher or lower temperatures....
. Examples are iron sulfide and many reactive metals including uranium
Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
, when powdered or sliced thinly. Pyrophoric materials are often water reactive
Water reactive

A water reactive substance is one that spontaneously undergoes a chemical reaction with water. Notable examples include alkali metals sodium through caesium....
 as well and will ignite when they contact water or humid air.






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Plutonium Pyrophoricity
A pyrophoric substance (from Greek purophoros, "fire-bearing") will ignite spontaneously; that is, its autoignition temperature
Autoignition temperature

The autoignition temperature or kindling point of a substance is the lowest temperature at which it will Spontaneous combustion in a normal atmosphere without an external source of ignition, such as a flame or spark....
 is below room temperature
Room temperature

Room temperature is a common term to denote a certain temperature within enclosed space at which humans are accustomed.Room temperature is thus often indicated by general human comfort, with the common range of 10celsius to 23?C , though climate may acclimatize people to higher or lower temperatures....
. Examples are iron sulfide and many reactive metals including uranium
Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
, when powdered or sliced thinly. Pyrophoric materials are often water reactive
Water reactive

A water reactive substance is one that spontaneously undergoes a chemical reaction with water. Notable examples include alkali metals sodium through caesium....
 as well and will ignite when they contact water or humid air. They can be handled safely in atmospheres of argon
Argon

Argon is a chemical element designated by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table ....
 or (with few exceptions) nitrogen
Nitrogen

Nitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674?. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere....
. Most pyrophoric fires should be extinguished with a Class D fire extinguisher
Fire extinguisher

A fire extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations. It is not intended for use on an out-of-control fire, such as one which has reached the ceiling, endangers the user , or otherwise requires the expertise of a fire department....
 for burning metals.

Uses


The creation of spark
Spark

A spark is a small airborne ember or particle of red-hot matter.Spark may also refer to:In science:* An electric spark, usually with a flash and a sharp noise, may be:...
s from metals is based on the pyrophoricity of small metal particles. This can be useful, including: the sparking mechanisms in lighter
Lighter

A lighter is a portable device used to create a flame. It consists of a metal or plastic container filled with lighter fluid , as well as a means of Combustion and some provision for extinguishing the flame, by depriving it of either air or fuel....
s and various toys, using ferrocerium
Ferrocerium

Ferrocerium is a man-made metallic material that has the ability to give off a large number of hot sparks when scraped against a rough surface , such as ridged steel....
; starting fires without matches, using a firesteel
Firesteel

A Fire striker is a piece of high-carbon steel used for striking a spark, usually kept in a tinderbox together with flint and tinder. From the Iron Age onwards, the use of flint and steel was the most common method of fire lighting prior to the invention of the friction match....
; the flintlock
Flintlock

Flintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced about 1630, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the matchlock and wheellock mechanisms....
 mechanism in firearms; and spark testing metals
Spark testing metals

Spark testing of metals is done by noting the type of sparks that issue from a piece of steel that has been put to a grinding wheel, From this one can deduce with some accuracy the type of alloy present ....
.

Safe handling of pyrophoric materials


Liquids


Small amounts of pyrophoric liquids are often supplied in a glass bottle with a PTFE lined septum. Larger amounts are supplied in metal tanks similar to gas cylinders, designed so a needle can fit through the valve opening. A syringe, carefully dried and flushed of air with an inert gas, is used to extract the liquid from its container.

Solids


Pyrophoric solids require the use of a sealed glove box flushed with inert gas. Glove boxes are expensive, and require maintenance. Thus, many pyrophoric solids are sold as solutions, or dispersions in mineral oil or lighter hydrocarbon solvents. Mildly pyrophoric solids (such as lithium aluminium hydride
Lithium aluminium hydride

Lithium aluminium hydride , commonly abbreviated to LAH, is a reducing agent used in organic synthesis. It is more powerful than the related reagent sodium borohydride due to the weaker Al-H bond compared to the B-H bond....
 and sodium hydride
Sodium hydride

Sodium hydride is the chemical compound with the formula NaH. It is primarily used as a strong base in organic synthesis. NaH is representative of the saline hydrides, meaning it is a salt-like hydride, composed of Na+ and H- ions, in contrast to the more molecular hydrides such as borane, methane, ammonia and water....
) can be handled in the air for brief periods of time, but the containers must be flushed with inert gas before storage.

Disposal


Small amounts of pyrophoric materials and empty containers must be disposed of carefully, by quenching the residue. Less reactive substances can be disposed of by diluting heavily with an unreactive solvent like hexane
Hexane

Hexane is an alkane hydrocarbon with the chemical formula CH34CH3 or C6H14. The "hex" prefix refers to its six carbons, while the "ane" ending indicates that its carbons are connected by single bonds....
, placing the container in a cooling bath
Cooling bath

A cooling bath is a mixture used in a laboratory when low temperatures are needed, for example to conduct low-temperature chemical reactions , to collect highly volatile liquids from distillation, or in cold traps....
, and adding water dropwise. More reactive substances can be quenched by slowly adding the dilute solution to dry ice
Dry ice

Dry ice is solid carbon dioxide. It is commonly used as a versatile cooling agent.Dry ice Sublimation , changing directly to a gas at atmospheric pressure....
, then adding a mildly reactive substance, which does not freeze in dry ice, to the mixture (wet diethyl ether
Diethyl ether

Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a characteristic odor....
, acetone
Acetone

Acetone is the organic compound with the chemical formula OC2. This colorless, mobile, flammable liquid is the simplest example of the ketones....
, isopropyl alcohol
Isopropyl alcohol

Isopropyl alcohol is a common name for isopropanol, a colorless, flammable chemical compound with a strong odor. It has the molecular formula C3H7OH and is the simplest example of a Alcohol#Primary.2C secondary.2C and tertiary alcohols, where the alcohol carbon is attached to two other carbons....
, and methanol
Methanol

Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a chemical compound with chemical formula carbonhydrogen3oxygenhydrogen ....
 are often used)

List of pyrophoric materials


Solids


  • Alkylated metal alkoxide
    Alkoxide

    An alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They can be written as RO–, where R is the organic substituent....
    s or nonmetal halides (diethylethoxyaluminium, dichloro(methyl)silane)
  • Alkali metal
    Alkali metal

    The alkali metals are a chemical series of chemical elements comprising Periodic table group of the periodic table: lithium , sodium , potassium , rubidium , caesium , and francium ....
    s (sodium
    Sodium

    Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
    , potassium
    Potassium

    Potassium is a chemical element. It has the symbol K , atomic number 19, and atomic mass 39.0983. Potassium was first isolated from potash, hence the name....
    )
  • Copper fuel cell catalysts, e.g., Cu/ZnO/Al2O3
  • Grignard reagents
    Grignard reaction

    The Grignard reaction, named after the French chemist Fran?ois Auguste Victor Grignard, is an organometallic chemistry chemical reaction in which alkyl- or aryl-magnesium halides , act as nucleophiles, attack electrophilic carbon atoms that are present within polar bonds to yield a carbon-carbon bond , thus altering hybridization about the r...
     (compounds of the form RMgX)
  • Finely divided metals (iron
    Iron

    Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
    , magnesium
    Magnesium

    Magnesium is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.Magnesium, an alkaline earth metal, is the ninth most abundance of the chemical elements in the universe by mass....
    , calcium
    Calcium

    Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft grey alkaline earth metal, and is the fifth most abundant element by mass in the earth's Crust ....
    , zirconium
    Zirconium

    Zirconium is a chemical element with the symbol Zr and atomic number 40. It is a lustrous, gray-white, strong transition metal that resembles titanium....
    , uranium
    Uranium

    Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
    , titanium
    Titanium

    Titanium is a chemical element with the symbol Ti and atomic number 22. Sometimes called the ?space age metal?, it has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver colour....
    , bismuth
    Bismuth

    Bismuth is a chemical element that has the symbol Bi and atomic number 83. This heavy, brittle, white crystalline trivalent poor metal has a pink tinge and chemically resembles arsenic and antimony....
    , hafnium
    Hafnium

    Hafnium is a chemical element with the element symbol Hf and atomic number 72. A lustre , silvery gray, tetravalence, transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals....
    )
  • Used hydrogenation
    Hydrogenation

    Hydrogenation is the chemical reaction that results from the addition of hydrogen . The process is usually employed to a redox or Saturation organic compounds....
     catalysts such as Raney nickel
    Raney nickel

    Raney nickel is a solid catalyst composed of fine grains of a nickel-aluminium alloy, used in many industrial processes. It was developed in 1926 by United States engineer Murray Raney as an alternative catalyst for the hydrogenation of vegetable oils in industrial processes....
     (especially hazardous because of the adsorbed hydrogen)
  • Metal hydride
    Hydride

    Hydride is the name given to the Electric charge ion of hydrogen, H-. Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe Chemical compound of hydrogen with other chemical element, particularly those of Periodic table group 1–16....
    s or nonmetal hydride
    Hydride

    Hydride is the name given to the Electric charge ion of hydrogen, H-. Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe Chemical compound of hydrogen with other chemical element, particularly those of Periodic table group 1–16....
    s (germane
    Germane

    Germane is the chemical compound with the formula germaniumhydrogen, and the germanium Analog of methane. It is the simplest germanium hydride and one of the most useful compounds of germanium....
    , diborane
    Diborane

    Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless gas at room temperature with a repulsively sweet odor....
    , sodium hydride
    Sodium hydride

    Sodium hydride is the chemical compound with the formula NaH. It is primarily used as a strong base in organic synthesis. NaH is representative of the saline hydrides, meaning it is a salt-like hydride, composed of Na+ and H- ions, in contrast to the more molecular hydrides such as borane, methane, ammonia and water....
    , lithium aluminium hydride
    Lithium aluminium hydride

    Lithium aluminium hydride , commonly abbreviated to LAH, is a reducing agent used in organic synthesis. It is more powerful than the related reagent sodium borohydride due to the weaker Al-H bond compared to the B-H bond....
    , uranium trihydride)
  • Iron Sulfide: often encountered in oil and gas facilities where corrosion products in steel plant equipment can ignite if exposed to air.
  • Partially or fully alkylated derivatives of metal and nonmetal hydride
    Hydride

    Hydride is the name given to the Electric charge ion of hydrogen, H-. Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe Chemical compound of hydrogen with other chemical element, particularly those of Periodic table group 1–16....
    s (diethylaluminium hydride, trimethylaluminium
    Trimethylaluminium

    Trimethylaluminium is the chemical compound with the formula aluminium26, abbreviated as Al2Me6, 2 or the abbreviation TMA....
    , butyllithium, triethylboron)
  • Uranium
    Uranium

    Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
     is pyrophoric, as shown by the vaporization of depleted uranium
    Depleted uranium

    Depleted uranium is uranium primarily composed of the isotope uranium-238 . Natural uranium is about 99.27 percent U-238, 0.72 percent uranium-235, and 0.0055 percent uranium-234....
     penetrator rounds into burning dust upon impact with their targets. In finely divided form it is readily ignitable, and uranium scrap from machining operations is subject to spontaneous ignition.
  • Metal carbonyl
    Carbonyl

    In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double bond to an oxygen atom : C=O.The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex ; in this situation, carbon is triple-bonded to oxygen : C=O....
    s (dicobalt octacarbonyl
    Dicobalt octacarbonyl

    Dicobalt octacarbonyl is the chemical compound Co28. This metal carbonyl is a versatile reagent in organometallic chemistry and organic synthesis....
    , nickel carbonyl
    Nickel carbonyl

    Nickel carbonyl is a colorless organometallic complex that is a versatile reagent, first described in 1890 by Ludwig Mond. It was the first metal simple carbonyl complex to be reported....
    )
  • Methanetellurol (CH3TeH)
  • Phosphorus
    Phosphorus

    Phosphorus is the chemical element that has the symbol P and atomic number 15. The name comes from the and . A Valency nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate minerals....
     (white, or yellow)
  • Plutonium
    Plutonium

    Plutonium is a rare transuranic radioactive chemical element. It is an actinide metal of silvery-white appearance that tarnishes when exposed to air, forming a dull coating when plutonium oxide....
    : several compounds are pyrophoric, and it causes some of the most serious fires occurring in United States Department of Energy
    United States Department of Energy

    The United States Department of Energy is a United States Cabinet-level department of the United States government of the United States responsible for Energy policy of the United States and nuclear safety....
     facilities.

Gases


  • Arsine
    Arsine

    Arsine is the chemical chemical compound with the Chemical formula arsenichydrogen3. This flammable, pyrophoric, and highly toxic gas is the simplest compound of arsenic....
  • Diborane
    Diborane

    Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless gas at room temperature with a repulsively sweet odor....
  • Phosphine
    Phosphine

    Phosphine is the common name for phosphorus trihydride , also known by the IUPAC name phosphane and, occasionally, phosphamine....
  • Silane
    Silane

    Silane is a chemical compound with chemical formula siliconhydrogen4. It is the silicon Analog of methane. At room temperature, silane is a gas, and is pyrophoric ? it undergoes spontaneous combustion in air, without the need for external ignition....


Liquids


  • Hydrazine
    Hydrazine

    Hydrazine is a chemical compound with the chemical formula N2H4. It is a colourless liquid with an ammonia-like odor and is derived from the same industrial chemistry processes that manufacture ammonia....
  • Metalorganics
    Metalorganics

    Metalorganic compounds are a class of chemical compounds that contain metals and organic ligands. Metalorganic compounds are used extensively in materials science in applications such as metalorganic vapour phase epitaxy or sol-gel processing using alkoxides....
     of main group metals (e.g. aluminium
    Aluminium

    Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
    , gallium
    Gallium

    Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the Ga salt, in trace amounts in bauxite and zinc ores....
    , indium
    Indium

    Indium is a chemical element with chemical symbol In and atomic number 49. This rare, soft, malleable and easily Fusible alloy Post-transition metal is chemically similar to aluminium or gallium but more closely resembles zinc ....
    , zinc
    Zinc

    Zinc is a metallic chemical element with the symbol Zn and atomic number 30. It is a first-row transition metal of the group 12 element of the periodic table....
     and cadmium
    Cadmium

    Cadmium is a chemical element with the symbol Cd and atomic number 48. A relatively abundant , soft, bluish-white, transition metal, cadmium is known to cause cancer and occurs with zinc ores....
     etc.)
  • Triethylborane
    Triethylborane

    Triethylborane , also called triethylborine and triethylboron, is an organoborane , a near-colorless to yellowish transparent liquid with pungent diethyl ether-like odor....


External links


  • US Dept. of Energy Handbook,