iso	NA	half-life	DM	DE (MeV)	DP
⁵⁴Fe	5.8%	>3.1×10²²y	2ε capture	?	⁵⁴Cr
⁵⁵Fe	syn	2.73 y	ε capture	0.231	⁵⁵Mn
⁵⁶Fe	91.72%	⁵⁶Fe is stable with 30 neutrons
⁵⁷Fe	2.2%	⁵⁷Fe is stable with 31 neutrons
⁵⁸Fe	0.28%	⁵⁸Fe is stable with 32 neutrons
⁵⁹Fe	syn	44.503 d	β⁻	1.565	⁵⁹Co
⁶⁰Fe	syn	2.6×10⁶ y	β⁻	3.978	⁶⁰Co

Iron is a chemical element with the symbol Fe (from Latin: ferrum) and atomic number 26. It is a metal in the first transition series. It is the most common element (by mass) forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. Iron's very common presence in rocky planets like Earth is due to its abundant production as a result of fusion in high-mass stars, where the production of nickel-56 (which decays to iron) is the last nuclear fusion reaction that is exothermic. This allows radioactive nickel to become the last element to be produced before collapse of a supernova leads to events that scatters this precursor radionuclide of iron into space.

Like other Group 8 elements, iron exists in a wide range of oxidation states, −2 to + 6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen and water. Fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give iron oxides, also known as rust. Unlike many other metals which form passivating oxide layers, iron oxides occupy more volume than iron metal, and thus iron oxides flake off and expose fresh surfaces for corrosion.

Iron metal has been used since ancient times, though lower-melting copper alloys were used first in history. Pure iron is soft (softer than aluminium), but is unobtainable by smelting. The material is significantly hardened and strengthened by impurities from the smelting process, such as carbon. A certain proportion of carbon (between 0.2% and 2.1%) produces steel, which may be up to 1000 times harder than pure iron. Crude iron metal is produced in blast furnaces, where ore is reduced by coke to cast iron, which has a high carbon content. Further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and low carbon iron alloys with other metals (alloy steels) are by far the most common metals in industrial use, due to their great range of desirable properties.

Iron chemical compounds, which include ferrous and ferric compounds, have many uses. Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. It forms binary compounds with the halogens and the chalcogens. Among its organometallic compounds, ferrocene was the first sandwich compound discovered.

Iron plays an important role in biology, forming complexes with molecular oxygen in hemoglobin and myoglobin; these two compounds are common oxygen transport proteins in vertebrates. Iron is also the metal used at the active site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants and animals.

Characteristics

Mechanical properties

Characteristic values of tensile strength (TS) and Brinell hardness (BH) of different forms of iron.^[1]^[2]
Material	TS (MPa)	BH (Brinell)
Iron whiskers	11000
Ausformed (hardened) steel	2930	850–1200
Martensitic steel	2070	600
Bainitic steel	1380	400
Pearlitic steel	1200	350
Cold-worked iron	690	200
Small-grain iron	340	100
Carbon-containing iron	140	40
Pure, single-crystal iron	10	3

Mechanical properties of iron and its alloys are evaluated using a variety of tests, such as the Brinell test, Rockwell test, or tensile strength tests, among others; the results on iron are so consistent that iron is often used to calibrate measurements or to relate the results of one test to another.^[2]^[3] Those measurements reveal that mechanical properties of iron crucially depend on purity: Purest research-purpose single crystals of iron are softer than aluminium. Addition of only 10 parts per million of carbon doubles their strength.^[1] The hardness increases rapidly with carbon content up to 0.2% and saturates at ~0.6%.^[4] The purest industrially produced iron (about 99.99% purity) has a hardness of 20–30 Brinell.^[5]

Phase diagram and allotropes

Main article: Allotropes of iron

Iron represents an example of allotropy in a metal. There are at least four allotropic forms of iron, known as α, γ, δ, and ε; at very high pressures, some controversial experimental evidence exists for a phase β stable at very high pressures and temperatures.^[6]

Low-pressure phase diagram of pure iron

As molten iron cools down it crystallizes at 1538 °C into its δ allotrope, which has a body-centered cubic (bcc) crystal structure. As it cools further its crystal structure changes to face-centered cubic (fcc) at 1394 °C, when it is known as γ-iron, or austenite. At 912 °C the crystal structure again becomes bcc as α-iron, or ferrite, is formed, and at 770 °C (the Curie point, T_c) iron becomes magnetic. As the iron passes through the Curie temperature there is no change in crystalline structure, but there is a change in "domain structure", where each domain contains iron atoms with a particular electronic spin. In unmagnetized iron, all the electronic spins of the atoms within one domain are in the same direction; the neighboring domains point in various directions and thus cancel out. In magnetized iron, the electronic spins of all the domains are aligned, so that the magnetic effects of neighboring domains reinforce each other. Although each domain contains billions of atoms, they are very small, about 10 micrometres across.^[7]. At pressures above approximately 10 GPa and temperatures of a few hundred kelvin or less, α-iron changes into a hexagonal close-packed (hcp) structure, which is also known as ε-iron; the higher-temperature γ-phase also changes into ε-iron, but does so at higher pressure. The β-phase, if it exists, would appear at pressures of at least 50 GPa and temperatures of at least 1500 K; it has been thought to have an orthorhombic or a double hcp structure.^[6]

Iron is of greatest importance when mixed with certain other metals and with carbon to form steels. There are many types of steels, all with different properties, and an understanding of the properties of the allotropes of iron is key to the manufacture of good quality steels.

α-iron, also known as ferrite, is the most stable form of iron at normal temperatures. It is a fairly soft metal that can dissolve only a small concentration of carbon (no more than 0.021% by mass at 910 °C).^[8]

Above 912 °C and up to 1400 °C α-iron undergoes a phase transition from bcc to the fcc configuration of γ-iron, also called austenite. This is similarly soft and metallic but can dissolve considerably more carbon (as much as 2.04% by mass at 1146 °C). This form of iron is used in the type of stainless steel used for making cutlery, and hospital and food-service equipment.^[7]

The high-pressure phases of iron are important as endmember models for the solid parts of planetary cores. The inner core of the Earth is generally assumed to consist essentially of an iron-nickel alloy with ε (or β) structure.

The melting point of iron is experimentally well constrained for pressures up to approximately 50 GPa. For higher pressures, different studies placed the γ-ε-liquid triple point at pressures differing by tens of gigapascals and yielded differences of more than 1000 K for the melting point. Generally speaking, molecular dynamics computer simulations of iron melting and shock wave experiments suggest higher melting points and a much steeper slope of the melting curve than static experiments carried out in diamond anvil cells.^[9]

Isotopes

Main article: Isotopes of iron

Naturally occurring iron consists of four stable isotopes: 5.845% of ⁵⁴Fe, 91.754% of ⁵⁶Fe, 2.119% of ⁵⁷Fe and 0.282% of ⁵⁸Fe. Of these stable isotopes, only ⁵⁷Fe has a nuclear spin (−1/2). The nuclide ⁵⁴Fe is predicted to undergo double beta decay, but this process had never been observed experimentally for these nuclei, and only the lower limit on the half-life was established: t_1/2>3.1×10²² years.

⁶⁰Fe is an extinct radionuclide of long half-life (2.6 million years).^[10] It is not found on Earth, but its ultimate decay product is forms part of the natural abundance of the stable nuclide nickel-60.

Much of the past work on measuring the isotopic composition of Fe has focused on determining ⁶⁰Fe variations due to processes accompanying nucleosynthesis (i.e., meteorite studies) and ore formation. In the last decade however, advances in mass spectrometry technology have allowed the detection and quantification of minute, naturally occurring variations in the ratios of the stable isotopes of iron. Much of this work has been driven by the Earth and planetary science communities, although applications to biological and industrial systems are beginning to emerge.^[11]

The most abundant iron isotope ⁵⁶Fe is of particular interest to nuclear scientists as it represents the most common endpoint of nucleosynthesis. It is often cited, falsely, as the isotope of highest binding energy, a distinction which actually belongs to nickel-62.^[12] Since ⁵⁶Ni is easily produced from lighter nuclei in the alpha process in nuclear reactions in supernovae (see silicon burning process), nickel-56 (14 alpha particles) is the endpoint of fusion chains inside extremely massive stars, since addition of another alpha particle would result in zinc-60, which requires a great deal more energy. This nickel-56, which has a half-life of about 6 days, is therefore made in quantity in these stars, but soon decays by two successive positron emissions within supernova decay products in the supernova remnant gas cloud, first to radioactive cobalt-56, and then stable iron-56. This last nuclide is therefore common in the universe, relative to other stable metals of approximately the same atomic weight.

In phases of the meteorites Semarkona and Chervony Kut a correlation between the concentration of ⁶⁰Ni, the daughter product of ⁶⁰Fe, and the abundance of the stable iron isotopes could be found which is evidence for the existence of ⁶⁰Fe at the time of formation of the solar system. Possibly the energy released by the decay of ⁶⁰Fe contributed, together with the energy released by decay of the radionuclide ²⁶Al, to the remelting and differentiation of asteroids after their formation 4.6 billion years ago^{[citation needed]}. The abundance of ⁶⁰Ni present in extraterrestrial material may also provide further insight into the origin of the solar system and its early history.

Nuclei of iron atoms have some of the highest binding energies per nucleon, surpassed only by the nickel isotope ⁶²Ni. This is formed by nuclear fusion in stars. Although a further tiny energy gain could be extracted by synthesizing ⁶²Ni, conditions in stars are unsuitable for this process to be favored. Elemental distribution on Earth greatly favors iron over nickel, and also presumably in supernova element production.^[13]

Iron-56 is the heaviest stable isotope produced by the alpha process in stellar nucleosynthesis; elements heavier than iron and nickel require a supernova for their formation. Iron is the most abundant element in the core of red giants, and is the most abundant metal in iron meteorites and in the dense metal cores of planets such as Earth.

Nucleosynthesis

Iron is created by extremely large, extremely hot (over 2.5 billion kelvin) stars, through a process called the silicon burning process. It is the heaviest stable element to be produced in this manner. The process starts with the second largest stable nucleus created by silicon burning: calcium. One stable nucleus of calcium fuses with one helium nucleus, creating unstable titanium. Before the titanium decays, it can fuse with another helium nucleus, creating unstable chromium. Before the chromium decays, it can fuse with another helium nucleus, creating unstable iron. Before the iron decays, it can fuse with another helium nucleus, creating unstable nickel-56. Any further fusion of nickel-56 consumes energy instead of producing energy, so after the production of nickel-56, the star does not produce the energy necessary to keep the core from collapsing. Eventually, the nickel-56 decays to unstable cobalt-56 which, in turn decays to stable iron-56 When the core of the star collapses, it creates a Supernova. Supernovas also create additional forms of stable iron via the r-process.

Occurrence

Planetary occurrence

Iron meteorites of similar composition of Earth's inner and outer core

Iron is the sixth most abundant element in the Universe, formed as the final step of nucleosynthesis, by silicon fusing in massive stars. Metallic iron is rarely found on the surface of the earth because it tends to oxidize, but its oxides are pervasive and represent the primary ores. While it makes up about 5% of the Earth's crust, both the Earth's inner and outer core are believed to consist largely of an iron-nickel alloy constituting 35% of the mass of the Earth as a whole. Iron is consequently the most abundant element on Earth, but only the fourth most abundant element in the Earth's crust.^[14]^[15] Most of the iron in the crust is found combined with oxygen as iron oxide minerals such as hematite and magnetite. Large deposits of iron are found in banded iron formations. These geological formations are a type of rock consisting of repeated thin layers of iron oxides, either magnetite (Fe₃O₄) or hematite (Fe₂O₃), alternating with bands of iron-poor shale and chert. The banded iron formations are common in the time between 3,700 million years ago and 1,800 million years ago^[16]^[17]

About 1 in 20 meteorites consist of the unique iron-nickel minerals taenite (35–80% iron) and kamacite (90–95% iron). Although rare, iron meteorites are the main form of natural metallic iron on the Earth's surface.^[18] It was proven by Mössbauer spectroscopy that the red color of the surface of Mars is derived from an iron oxide-rich regolith.^[19]

In-use stocks in society

According to the International Resource Panel's Metal Stocks in Society report, the global per capita stock of iron in use in society is 2200kg. Much of this is in more-developed countries (7000–14000kg per capita) rather than less-developed countries (2000kg per capita).

Chemistry and compounds

Oxidation state	Representative compound
−2	Disodium tetracarbonylferrate (Collman's reagent)
−1
0	Iron pentacarbonyl
1	Cyclopentadienyliron dicarbonyl dimer ("Fp₂")
2	Ferrous sulfate, ferrocene
3	Ferric chloride, ferrocenium tetrafluoroborate
4	Barium ferrate(IV)
5
6	Potassium ferrate

Binary compounds

Iron reacts with oxygen in the air to form various oxide and hydroxide compounds; the most common are iron(II,III) oxide (Fe₃O₄), and iron(III) oxide (Fe₂O₃). Iron(II) oxide also exists, though it is unstable at room temperature. These oxides are the principal ores for the production of iron (see bloomery and blast furnace). They are also used in the production of ferrites, useful magnetic storage media in computers, and pigments. The best known sulfide is iron pyrite (FeS₂), also known as fool's gold owing to its golden luster.^[21]

The binary ferrous and ferric halides are well known, with the exception of ferric iodide. The ferrous halides typically arise from treating iron metal with the corresponding binary halogen acid to give the corresponding hydrated salts.^[21]

Fe + 2 HX → FeX₂ + H₂

Iron reacts with fluorine, chlorine, and bromine to give the corresponding ferric halides, ferric chloride being the most common:

2 Fe + 3 X₂ → 2 FeX₃ (X = F, Cl, Br)

Coordination and organometallic compounds

History

Main article: History of ferrous metallurgy

Wrought iron

A circle, with a short, simple arrow shape extending diagonally upwards and rightwards from its edge

The symbol for Mars has been used since antiquity to represent iron.

An pillar, slightly fluted, with some ornamentation at its top. It is black, slightly weathered to a dark brown near the base. It is around 7 meters (22 feet) tall. It stands upon a raised circular base of stone, and is surrounded by a short, square fence.

The Delhi iron pillar is an example of the iron extraction and processing methodologies of India. The iron pillar at Delhi has withstood corrosion for the last 1600 years.

Iron objects of great age are much rarer than objects made of gold or silver due to the ease of corrosion of iron.^[31] Beads made of meteoric iron in 3500 B.C. or earlier were found in Gerzah, Egypt by G. A. Wainwright.^[32] The beads contain 7.5% nickel, which is a signature of meteoric origin since iron found in the Earth's crust has very little to no nickel content. Meteoric iron was highly regarded due to its origin in the heavens and was often used to forge weapons and tools or whole specimens placed in churches.^[32] Items that were likely made of iron by Egyptians date from 2500 to 3000 BC.^[31] Iron had a distinct advantage over bronze in warfare implements. It was much harder and more durable than bronze, although susceptible to rust. However, this is contested. Hittitologist Trevor Bryce argues that before advanced iron-working techniques were developed in Europe and India, cast-iron weapons used by early Mesopotamian armies had a tendency to shatter in combat, due to their high carbon content.^[33]

The first iron production started in the Middle Bronze Age but it took several centuries before iron displaced bronze. Samples of smelted iron from Asmar, Mesopotamia and Tall Chagar Bazaar in northern Syria were made sometime between 2700 and 3000 BC.^[34] The Hittites appear to be the first to understand the production of iron from its ores and regard it highly in their society.^[27] They began to smelt iron between 1500 and 1200 BC and the practice spread to the rest of the Near East after their empire fell in 1180 BC.^[34] The subsequent period is called the Iron Age. Iron smelting, and thus the Iron Age, reached Europe two hundred years later and arrived in Zimbabwe, Africa by the 8th century.^[34]

Artifacts from smelted iron occur in India from 1800 to 1200 BC,^[35] and in the Levant from about 1500 BC (suggesting smelting in Anatolia or the Caucasus).^[36]^[37]

The Book of Genesis, fourth chapter, verse 22 contains the first mention of iron in the Old Testament of the Bible; "Tubal-cain, an instructor of every artificer in brass and iron."^[31] Other verses allude to iron mining (Job 28:2), iron used as a stylus (Job 19:24), furnace (Deuteronomy 4:20), chariots (Joshua 17:16), nails (I Chron. 22:3), saws and axes (II Sam. 12:31), and cooking utensils (Ezekiel 4:3).^[38] The metal is also mentioned in the New Testament, for example in Acts chapter 12 verse 10, "[Peter passed through] the iron gate that leadeth unto the city" of Antioch.^[39] The Quran referred to Iron 1400 years ago.

Iron working was introduced to Greece in the late 11th century BC.^[40] The spread of ironworking in Central and Western Europe is associated with Celtic expansion. According to Pliny the Elder, iron use was common in the Roman era.^[32] The annual iron output of the Roman Empire is estimated at 84,750 t,^[41] while the similarly populous Han China produced around 5,000 t.^[42]

During the Industrial Revolution in Britain, Henry Cort began refining iron from pig iron to wrought iron (or bar iron) using innovative production systems. In 1783 he patented the puddling process for refining iron ore. It was later improved by others including Joseph Hall.

Cast iron

Cast iron was first produced in China about 550 BC,^[43] but was hardly in Europe until the medieval period.^[44]^[45] During the medieval period, means were found in Europe of producing wrought iron from cast iron (in this context known as pig iron) using finery forges. For all these processes, charcoal was required as fuel.

Coalbrookdale by Night, 1801. Blast furnaces light the iron making town of Coalbrookdale.

Medieval blast furnaces were about 10 feet (3.0 m) tall and made of fireproof brick; forced air was usually provided by hand-operated bellows.^[45] Modern blast furnaces have grown much bigger.

In 1709, Abraham Darby I established a coke-fired blast furnace to produce cast iron. The ensuing availability of inexpensive iron was one of the factors leading to the Industrial Revolution. Toward the end of the 18th century, cast iron began to replace wrought iron for certain purposes, because it was cheaper. Carbon content in iron wasn't implicated as the reason for the differences in properties of wrought iron, cast iron and steel until the 18th century.^[34]

Since iron was becoming cheaper and more plentiful, it also became a major structural material following the building of the innovative first iron bridge in 1778.

Steel

Foundations of modern chemistry

Antoine Lavoisier used the reaction of water steam with metallic iron inside an incandescent iron tube to produce hydrogen in his experiments leading to the demonstration of the mass conservation. Anaerobic oxidation of iron at high temperature can be schematically represented by the following reactions:

Fe + H₂O → FeO + H₂

2 Fe + 3 H₂O → Fe₂O₃ + 3 H₂

3 Fe + 4 H₂O → Fe₃O₄ + 4 H₂

Recent discoveries

discovery of Mössbauer effect
many enzymes use iron in the catalytic center
Nickel-56 is the natural end product of silicon burning in massive stars. However Nickel-56 decays to cobalt-56 and then to stable iron-56, ultimately making iron the most abundant heavy element produced by that nucleosynthesis.^[47]
superconductivity?
magnetic effect
ferrocene

Industrial production

Blast furnace

Main article: Blast furnace

Ninety percent of all mining of metallic ores is for the extraction of iron^{[citation needed]}. Industrially, iron production involves iron ores, principally hematite (nominally Fe₂O₃) and magnetite (Fe₃O₄) in a carbothermic reaction (reduction with carbon) in a blast furnace at temperatures of about 2000 °C. In a blast furnace, iron ore, carbon in the form of coke, and a flux such as limestone (which is used to remove silicon dioxide impurities in the ore which would otherwise clog the furnace with solid material) are fed into the top of the furnace, while a massive blast of heated air, about 4 tons per ton of iron,^[45] is forced into the furnace at the bottom.

Iron output in 2005

In the furnace, the coke reacts with oxygen in the air blast to produce carbon monoxide:

2 C + O₂ → 2 CO

The carbon monoxide reduces the iron ore (in the chemical equation below, hematite) to molten iron, becoming carbon dioxide in the process:

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

Some iron in the high-temperature lower region of the furnace reacts directly with the coke:

2 Fe₂O₃ + 3 C → 4 Fe + 3 CO₂

The flux is present to melt impurities in the ore, principally silicon dioxide sand and other silicates. Common fluxes include limestone (principally calcium carbonate) and dolomite (calcium-magnesium carbonate). Other fluxes may be used depending on the impurities that need to be removed from the ore. In the heat of the furnace the limestone flux decomposes to calcium oxide (also known as quicklime):

CaCO₃ → CaO + CO₂

Then calcium oxide combines with silicon dioxide to form a liquid slag.

CaO + SiO₂ → CaSiO₃

The slag melts in the heat of the furnace. In the bottom of the furnace, the molten slag floats on top of the denser molten iron, and apertures in the side of the furnace are opened to run off the iron and the slag separately. The iron, once cooled, is called pig iron, while the slag can be used as a material in road construction or to improve mineral-poor soils for agriculture^[45]

This heap of iron ore pellets will be used in steel production.

In 2005, approximately 1,544 million metric tons of iron ore were produced worldwide. According to the British Geological Survey, China was the top producer of iron ore with at least one quarter world share, followed by Brazil, Australia and India.

Direct iron reduction

Since coke is becoming more regulated due to environmental concerns, alternative methods of processing iron have been developed. One of them is known as direct iron reduction.^[45] It reduces iron ore to a powder substance called sponge iron, which is suitable for steelmaking. There are two main reactions that go on in the direct reduction process:

Natural gas is partially oxidized (with heat and a catalyst):

2 CH₄ + O₂ → 2 CO + 4 H₂

These gases are then treated with iron ore in a furnace, producing solid sponge iron:

Fe₂O₃ + CO + 2 H₂ → 2 Fe + CO₂ + 2 H₂O

Silica is removed by adding a flux, i.e. limestone, later.

Further processes

Main articles: Steelmaking and Ironworks

Iron-carbon phase diagram, various stable solid solution forms

Pig iron is not pure iron, but has 4–5% carbon dissolved in it with small amounts of other impurities like sulfur, magnesium, phosphorus and manganese. As the carbon is the major impurity, the iron (pig iron) becomes brittle and hard. This form of iron, also known as cast iron, is used to cast articles in foundries such as stoves, pipes, radiators, lamp-posts and rails.

Alternatively pig iron may be made into steel (with up to about 2% carbon) or wrought iron (commercially pure iron). Various processes have been used for this, including finery forges, puddling furnaces, Bessemer converters, open hearth furnaces, basic oxygen furnaces, and electric arc furnaces. In all cases, the objective is to oxidize some or all of the carbon, together with other impurities. On the other hand, other metals may be added to make alloy steels.

The hardness of the steel depends upon its carbon content: the higher the percentage of carbon, the greater the hardness and the lesser the malleability. The properties of the steel can also be changed by several methods.

Annealing involves the heating of a piece of steel to 700–800 °C for several hours and then gradual cooling. It makes the steel softer and more workable.

Steel may be hardened by cold working. The metal is bent or hammered into its final shape at a relatively cool temperature. Cold forging is the stamping of a piece of steel into shape by a heavy press. Wrenches are commonly made by cold forging. Cold rolling, which involves making a thinner but harder sheet, and cold drawing, which makes a thinner but stronger wire, are two other methods of cold working. To harden the steel, it is heated to red-hot and then cooled by quenching it in the water. It becomes harder and more brittle. If it is too hardened, it is then heated to a required temperature and allowed to cool. The steel thus formed is less brittle.

Heat treatment is another way to harden steel. The steel is heated red-hot, then cooled quickly. The iron carbide molecules are decomposed by the heat, but do not have time to reform. Since the free carbon atoms are stuck, it makes the steel much harder and stronger than before.^[45]

Sometimes both toughness and hardness are desired. A process called case hardening may be used. Steel is heated to about 900 °C then plunged into Oil or Water. Carbon from the oil can diffuse into the steel, making the surface very hard. The surface cools quickly, but the inside cools slowly, making an extremely hard surface and a durable, resistant inner layer.

Iron may be passivated by dipping it into a concentrated nitric acid solution. This forms a protective layer of oxide on the metal, protecting it from further corrosion.^[48]

Applications

Metallurgical

A graph of attenuation coefficient vs. energy between 1 meV and 100 keV for several photon scattering mechanisms.

Photon mass attenuation coefficient for iron.

Iron is the most widely used of all the metals, accounting for 95% of worldwide metal production.^{[citation needed]} Its low cost and high strength make it indispensable in engineering applications such as the construction of machinery and machine tools, automobiles, the hulls of large ships, and structural components for buildings. Since pure iron is quite soft, it is most commonly used in the form of steel.

Commercially available iron is classified based on purity and the abundance of additives. Pig iron has 3.5–4.5% carbon^[49] and contains varying amounts of contaminants such as sulfur, silicon and phosphorus. Pig iron is not a saleable product, but rather an intermediate step in the production of cast iron and steel from iron ore. Cast iron contains 2–4% carbon, 1–6% silicon, and small amounts of manganese. Contaminants present in pig iron that negatively affect material properties, such as sulfur and phosphorus, have been reduced to an acceptable level. It has a melting point in the range of 1420–1470 K, which is lower than either of its two main components, and makes it the first product to be melted when carbon and iron are heated together. Its mechanical properties vary greatly, dependent upon the form carbon takes in the alloy.

"White" cast irons contain their carbon in the form of cementite, or iron carbide. This hard, brittle compound dominates the mechanical properties of white cast irons, rendering them hard, but unresistant to shock. The broken surface of a white cast iron is full of fine facets of the broken carbide, a very pale, silvery, shiny material, hence the appellation.

In gray iron the carbon exists free as fine flakes of graphite, and also renders the material brittle due to the stress-raising nature of the sharp edged flakes of graphite. A newer variant of gray iron, referred to as ductile iron is specially treated with trace amounts of magnesium to alter the shape of graphite to spheroids, or nodules, vastly increasing the toughness and strength of the material.

Wrought iron contains less than 0.25% carbon.^[49] It is a tough, malleable product, but not as fusible as pig iron. If honed to an edge, it loses it quickly. Wrought iron is characterized by the presence of fine fibers of slag entrapped in the metal. Wrought iron is more corrosion resistant than steel. It has been almost completely replaced by mild steel for traditional "wrought iron" products and blacksmithing.

Mild steel corrodes more readily than wrought iron, but is cheaper and more widely available. Carbon steel contains 2.0% carbon or less,^[50] with small amounts of manganese, sulfur, phosphorus, and silicon. Alloy steels contain varying amounts of carbon as well as other metals, such as chromium, vanadium, molybdenum, nickel, tungsten, etc. Their alloy content raises their cost, and so they are usually only employed for specialist uses. One common alloy steel, though, is stainless steel. Recent developments in ferrous metallurgy have produced a growing range of microalloyed steels, also termed 'HSLA' or high-strength, low alloy steels, containing tiny additions to produce high strengths and often spectacular toughness at minimal cost.

Apart from traditional applications, iron is also used for protection from ionizing radiation. Although it is lighter than another traditional protection material, lead, it is much stronger mechanically. The attenuation of radiation as a function of energy is shown in the graph.

The main disadvantage of iron and steel is that pure iron, and most of its alloys, suffer badly from rust if not protected in some way. Painting, galvanization, passivation, plastic coating and bluing are all used to protect iron from rust by excluding water and oxygen or by cathodic protection.

Of compounds

Although its metallurgical role is dominant in terms of amounts, iron compounds are pervasive in industry as well being used in many niche uses. Iron catalysts are traditionally used in the Haber-Bosch Process for the production of ammonia and the Fischer-Tropsch process for conversion of carbon monoxide to hydrocarbons for fuels and lubricants.^[51] Powdered iron in an acidic solvent was used in the Bechamp reduction the reduction of nitrobenzene to aniline.^[52]

Iron(III) chloride finds use in water purification and sewage treatment, in the dyeing of cloth, as a coloring agent in paints, as an additive in animal feed, and as an etchant for copper in the manufacture of printed circuit boards.^[53] It can also be dissolved in alcohol to form tincture of iron.^[27] The other halides tend to be limited to laboratory uses.

Iron(II) sulfate is used as a precursor to other iron compounds. It is also used to reduce chromate in cement. It is used to fortify foods and treat iron deficiency anemia. These are its main uses. Iron(III) sulfate is used in settling minute sewage particles in tank water. Iron(II) chloride is used as a reducing flocculating agent, in the formation of iron complexes and magnetic iron oxides, and as a reducing agent in organic synthesis.

Biological role

Iron is abundant in biology. Iron-proteins are found in all living organisms, ranging from the evolutionarily primitive archaea to humans. The color of blood is due to the hemoglobin, an iron-containing protein. As illustrated by hemoglobin, iron often is bound to cofactors, e.g. in hemes. The iron-sulfur clusters are pervasive and include nitrogenase, the enzymes responsible for biological nitrogen fixation. Influential theories of evolution have invoked a role for iron sulfides, iron-sulfur world theory.^{[citation needed]}

Structure of Heme b, in the protein additional ligand(s) would be attached to Fe.

Main article: Human iron metabolism

Iron is a necessary trace element found in nearly all living organisms. Iron-containing enzymes and proteins, often containing heme prosthetic groups, participate in many biological oxidations and in transport. Examples of proteins found in higher organisms include hemoglobin, cytochrome (see high-valent iron), and catalase.^[54]

Bioinorganic compounds

The most famous bioinorganic compounds of iron are heme proteins: hemoglobin, myoglobin, and cytochrome P450. These compounds can transport gases, build enzymes, and be used in transferring electrons. Metalloproteins are a group of proteins with metal ion cofactors. Some examples of iron metalloproteins are ferritin and rubredoxin. Many enzymes vital to life contain iron, such as catalase, lipoxygenases, and IRE-BP.

Health and diet

Main article: Iron deficiency (medicine)

Iron is pervasive, but particularly rich sources of dietary iron include red meat, lentils, beans, poultry, fish, leaf vegetables, tofu, chickpeas, black-eyed peas, blackstrap molasses, fortified bread, and fortified breakfast cereals. Iron in low amounts is found in molasses, teff and farina. Iron in meat (heme iron) is more easily absorbed than iron in vegetables.^[55] Although some studies suggest that heme/hemoglobin from red meat has effects which may increase the likelihood of colorectal cancer,^[56]^[57] there is still some controversy,^[58] and even a few studies suggesting that there is not enough evidence to support such claims.^[59]

Iron provided by dietary supplements is often found as iron(II) fumarate, although iron sulfate is cheaper and is absorbed equally well. Elemental iron, or reduced iron, despite being absorbed at only one third to two thirds the efficiency (relative to iron sulfate),^[60] is often added to foods such as breakfast cereals or enriched wheat flour. Iron is most available to the body when chelated to amino acids^[61] and is also available for use as a common iron supplement. Often the amino acid chosen for this purpose is the cheapest and most common amino acid, glycine, leading to "iron glycinate" supplements.^[62] The Recommended Dietary Allowance (RDA) for iron varies considerably based on age, gender, and source of dietary iron (heme-based iron has higher bioavailability).^[63] Infants may require iron supplements if they are bottle-fed cow's milk.^[64] Blood donors and pregnant women are at special risk of low iron levels and are often advised to supplement their iron intake.^[65]

Uptake and storage

In cells, iron storage is carefully regulated; "free" iron ions do not exist as such. A major component of this regulation is the protein transferrin, which binds iron ions absorbed from the duodenum and carries it in the blood to cells.^[66] In animals, plants, and fungi, iron is often the metal ion incorporated into the heme complex. Heme is an essential component of cytochrome proteins, which mediate redox reactions, and of oxygen carrier proteins such as hemoglobin, myoglobin, and leghemoglobin. Inorganic iron also contributes to redox reactions in the iron-sulfur clusters of many enzymes, such as nitrogenase (involved in the synthesis of ammonia from nitrogen and hydrogen) and hydrogenase. Non-heme iron proteins include the enzymes methane monooxygenase (oxidizes methane to methanol), ribonucleotide reductase (reduces ribose to deoxyribose; DNA biosynthesis), hemerythrins (oxygen transport and fixation in Marine invertebrates) and purple acid phosphatase (hydrolysis of phosphate esters).

Iron distribution is heavily regulated in mammals, partly because iron ions have a high potential for biological toxicity.^[67]

Iron acquisition poses a problem for aerobic organisms because ferric iron is poorly soluble near neutral pH. Thus, bacteria have evolved high-affinity sequestering agents called siderophores.^[68]^[69]^[70]

Regulation of uptake

Main article: Hepcidin

Iron uptake is tightly regulated by the human body, which has no regulated physiological means of excreting iron. Only small amounts of iron are lost daily due to mucosal and skin epithelial cell sloughing, so control of iron levels is mostly by regulating uptake.^[71] Regulation of iron uptake is impaired in some people as a result of a genetic defect that maps to the HLA-H gene region on chromosome 6. In these people, excessive iron intake can result in iron overload disorders, such as hemochromatosis. Many people have a genetic susceptibility to iron overload without realizing it or being aware of a family history of the problem. For this reason, it is advised that people do not take iron supplements unless they suffer from iron deficiency and have consulted a doctor. Hemochromatosis is estimated to cause disease in between 0.3 and 0.8% of Caucasians.^[72]

MRI finds that iron accumulates in the hippocampus of the brains of those with Alzheimer's disease and in the substantia nigra of those with Parkinson disease.^[73]

Permeable reactive barriers

Zero-valent iron is the main reactive material for permeable reactive barriers.^{[citation needed]}

Precautions

NFPA 704
1 0 1
Fire diamond for powdered iron metal

Main article: Iron poisoning

Large amounts of ingested iron can cause excessive levels of iron in the blood. High blood levels of free ferrous iron react with peroxides to produce free radicals, which are highly reactive and can damage DNA, proteins, lipids, and other cellular components. Thus, iron toxicity occurs when there is free iron in the cell, which generally occurs when iron levels exceed the capacity of transferrin to bind the iron. Damage to the cells of the gastrointestinal tract can also prevent them from regulating iron absorption leading to further increases in blood levels. Iron typically damages cells in the heart, liver and elsewhere, which can cause significant adverse effects, including coma, metabolic acidosis, shock, liver failure, coagulopathy, adult respiratory distress syndrome, long-term organ damage, and even death.^[74] Humans experience iron toxicity above 20 milligrams of iron for every kilogram of mass, and 60 milligrams per kilogram is considered a lethal dose.^[75] Overconsumption of iron, often the result of children eating large quantities of ferrous sulfate tablets intended for adult consumption, is one of the most common toxicological causes of death in children under six.^[75] The Dietary Reference Intake (DRI) lists the Tolerable Upper Intake Level (UL) for adults as 45 mg/day. For children under fourteen years old the UL is 40 mg/day.

The medical management of iron toxicity is complicated, and can include use of a specific chelating agent called deferoxamine to bind and expel excess iron from the body.^[74]^[76]

References

^ ^a ^b Kohl, Walter H. (1995). Handbook of materials and techniques for vacuum devices. Springer. pp. 164–167. ISBN 1563963876. http://books.google.com/?id=-Ll6qjWB-RUC&pg=PA164.
^ ^a ^b Kuhn, Howard and Medlin, Dana (prepared under the direction of the ASM International Handbook Committee), ed (2000). ASM Handbook – Mechanical Testing and Evaluation. 8. ASM International. p. 275. ISBN 0871703890. http://www.gorni.eng.br/e/Gorni_SFHTHandbook.pdf.
^ "Hardness Conversion Chart". Maryland Metrics. http://mdmetric.com/tech/hardnessconversion.html. Retrieved 2010-05-23.
^ Raghavan, V. (2004). Materials Science and Engineering. PHI Learning Pvt. Ltd.. p. 218. ISBN 8120324552. http://books.google.com/?id=LgB5dkmPML0C&pg=PA218.
^ Takaji, Kusakawa; Toshikatsu, Otani (01/01/1964). "Properties of Various Pure Irons : Study on pure iron I". Tetsu-to-Hagane 50 (1): 42–47. http://ci.nii.ac.jp/naid/110001459778/en.
^ ^a ^b Boehler, Reinhard (2000). "High-pressure experiments and the phase diagram of lower mantle and core materials". Review of Geophysics (American Geophysical Union) 38 (2): 221–245. Bibcode 2000RvGeo..38..221B. doi:10.1029/1998RG000053.
^ ^a ^b Bramfitt, B. L.; Benscoter, Arlan O. (2002). "The Iron Carbon Phase Diagram". Metallographer's guide: practice and procedures for irons and steels. ASM International. pp. 24–28. ISBN 9780871707482. http://books.google.com/?id=hoM8VJHTt24C&pg=PA24.
^ Martin, John Wilson (2007). Concise encyclopedia of the structure of materials. Elsevier. p. 183. ISBN 0080451276. http://books.google.com/?id=xv420pEC2qMC&pg=PA183.
^ Boehler, Reinhard; Ross, M. (2007). "Properties of Rocks and Minerals — High-Pressure Melting". Mineral Physics. Treatise on Geophysics. 2. Elsevier. pp. 527–541.
^ Georges, Audi (2003). "The NUBASE Evaluation of Nuclear and Decay Properties". Nuclear Physics A (Atomic Mass Data Center) 729: 3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
^ Dauphas, N.; Rouxel, O. (2006). "Mass spectrometry and natural variations of iron isotopes". Mass Spectrometry Reviews 25 (4): 515–550. doi:10.1002/mas.20078. PMID 16463281. http://geosci.uchicago.edu/~dauphas/OLwebsite/PDFfiles/Dauphas_Rouxel_MSR06.pdf.
^ Fewell, M. P. (1995). "The atomic nuclide with the highest mean binding energy". American Journal of Physics 63 (7): 653. Bibcode 1995AmJPh..63..653F. doi:10.1119/1.17828.
^ "Iron and Nickel Abundances in H~II Regions and Supernova Remnants". June 14, 1995. http://www.aas.org/publications/baas/v27n2/aas186/abs/S3707.html. Retrieved 2010-05-23. .
^ "Iron: geological information". WebElements. http://www.webelements.com/iron/geology.html. Retrieved 2010-05-23. .
^ John W. Morgan*and Edward Anders (1980). "Chemical composition of Earth, Venus, and Mercury". Proc. Nat. Acad. Sci. 77 (12): 6973 –6977. Bibcode 1980PNAS...77.6973M. doi:10.1073/pnas.77.12.6973. PMC 350422. PMID 16592930. http://www.pnas.org/content/77/12/6973.
^ Lyons, T. W.; Reinhard, CT (2009). "Early Earth: Oxygen for heavy-metal fans". Nature 461 (7261): 179–181. Bibcode 2009Natur.461..179L. doi:10.1038/461179a. PMID 19741692.
^ Cloud, P. (1973). "Paleoecological Significance of the Banded Iron-Formation". Economic Geology 68 (7): 1135–1143. doi:10.2113/gsecongeo.68.7.1135.
^ Emiliani, Cesare (1992). "Meteorites". Planet earth: cosmology, geology, and the evolution of life and environment. Cambridge University Press. p. 152. ISBN 9780521409490. http://books.google.com/?id=QDU7AAAAIAAJ&pg=PA152.
^ Klingelhöfer, G.; Morris, R. V.; Souza, P. A.; Rodionov, D.; Schröder, C. (2007). "Two earth years of Mössbauer studies of the surface of Mars with MIMOS II". Hyperfine Interactions 170: 169–177. Bibcode 2006HyInt.170..169K. doi:10.1007/s10751-007-9508-5.
^ Nam, Wonwoo (2007). "High-Valent Iron(IV)–Oxo Complexes of Heme and Non-Heme Ligands in Oxygenation Reactions". Accounts of Chemical Research 40 (7): 522–531. doi:10.1021/ar700027f. PMID 17469792.
^ ^a ^b ^c ^d ^e ^f Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils; (1985). "Iron" (in German). Lehrbuch der Anorganischen Chemie (91–100 ed.). Walter de Gruyter. pp. 1125–1146. ISBN 3110075113.
^ Reiff, William Michael; Long, Gary J. (1984). "Mössbauer Spectroscopy and the Coordination Chemistry of Iron". Mössbauer spectroscopy applied to inorganic chemistry. Springer. pp. 245–283. ISBN 9780306416477.
^ Ware, Mike (1999). "An introduction in monochrome". Cyanotype: the history, science and art of photographic printing in Prussian blue. NMSI Trading Ltd. pp. 11–19. ISBN 9781900747073. http://books.google.com/?id=C-7I69gFIbMC&pg=PA11.
^ Gmelin, Leopold (1852). "Mercury and Iron". Hand-book of chemistry. 6. Cavendish Society. pp. 128–129. http://books.google.com/?id=nosMAAAAYAAJ&pg=PA128.
^ "Questions and Answers on Prussian Blue". http://www.fda.gov/Drugs/EmergencyPreparedness/BioterrorismandDrugPreparedness/ucm130337.htm. Retrieved 2009-06-06.
^ Thompson, D. F; Callen, ED (2004). "Soluble or Insoluble Prussian Blue for Radiocesium and Thallium Poisoning?". Annals of Pharmacotherapy 38 (9): 1509–1514. doi:10.1345/aph.1E024. PMID 15252192.
^ ^a ^b ^c ^d "Iron." Microsoft Student 2009 [DVD]. Redmond, WA: Microsoft Corporation, 2008.
^ Greenwood, Norman N.; Earnshaw, A. (1984). Chemistry of the Elements. Oxford: Pergamon. pp. 1282–86. ISBN 0-08-022057-6. .
^ Pierre Laszlo and Roald Hoffmann (2000) "Ferrocene: Ironclad History of Rashomon Tale?," Angewandte Chemie (International Edition), vol. 39, no. 1, pages 123–124.
^ Federman Neto, Alberto; Pelegrino, Alessandra Caramori; Darin, Vitor Andre (2004). "Ferrocene: 50 Years of Transition Metal Organometallic Chemistry — From Organic and Inorganic to Supramolecular Chemistry". ChemInform 35 (43). doi:10.1002/chin.200443242.
^ ^a ^b ^c Weeks 1968, p. 29.
^ ^a ^b ^c Weeks 1968, p. 31.
^ Trevor Bryce, "Hittite Warrior" (Osprey Publishing, London: 2007) pp. 22–23
^ ^a ^b ^c ^d ^e Weeks 1968, p. 32.
^ Tewari, Rakesh. "The origins of Iron Working in India: New evidence from the Central Ganga plain and the Eastern Vindhyas". State Archaeological Department. http://antiquity.ac.uk/projgall/tewari/tewari.pdf. Retrieved 2010-05-23.
^ Photos, E. (1989). "The Question of Meteoritic versus Smelted Nickel-Rich Iron: Archaeological Evidence and Experimental Results". World Archaeology (Taylor & Francis, Ltd.) 20 (3): 403–421. doi:10.1080/00438243.1989.9980081. JSTOR 124562.
^ Muhly, James D. (2003). "Metalworking/Mining in the Levant". In Lake, Richard Winona. Near Eastern Archaeology IN: Eisenbrauns. 180. pp. 174–183.
^ Weeks 1968, pp. 29–30.
^ Weeks 1968, p. 30.
^ Riederer, Josef; Wartke, Ralf-B.: "Iron", Cancik, Hubert; Schneider, Helmuth (eds.): Brill's New Pauly, Brill 2009
^ Craddock, Paul T. (2008): "Mining and Metallurgy", in: Oleson, John Peter (ed.): The Oxford Handbook of Engineering and Technology in the Classical World, Oxford University Press, ISBN 978-0-19-518731-1, p. 108
^ Wagner, Donald B.: "The State and the Iron Industry in Han China", NIAS Publishing, Copenhagen 2001, ISBN 87-87062-77-1, p. 73
^ Wagner, Donald B. (2003). "Chinese blast furnaces from the 10th to the 14th century". Historical Metallurgy 37 (1): 25–37. originally published in Wagner, Donald B. (2001). "Chinese blast furnaces from the 10th to the 14th century". West Asian Science, Technology, and Medicine 18: 41–74.
^ Giannichedda, Enrico (2007): "Metal production in Late Antiquity", in Technology in Transition AD 300–650 L. Lavan E.Zanini & A. Sarantis eds., Brill, Leiden; ISBN 90-04-16549-5 p. 200
^ ^a ^b ^c ^d ^e ^f Biddle, Verne; Parker, Gregory. Chemistry, Precision and Design. A Beka Book, Inc..
^ "A Brief History of Iron and Steel Production"
^ Wikipedia "Nickel-62"
^ http://www.euro-inox.org/pdf/map/Passivating_Pickling_EN.pdf
^ ^a ^b Camp, James McIntyre; Francis, Charles Blaine (1920). The Making, Shaping and Treating of Steel. Pittsburgh: Carnegie Steel Company. pp. 173–174. ISBN 1147644233. http://books.google.com/?id=P9MxAAAAMAAJ.
^ "Classification of Carbon and Low-Alloy Steels". http://www.keytometals.com/page.aspx?ID=CheckArticle&site=kts&NM=62. Retrieved 2008-01-05.
^ Kolasinski, Kurt W. (2002). "Where are Heterogenous Reactions Important". Surface science: foundations of catalysis and nanoscience. John Wiley and Sons. pp. 15–16. ISBN 9780471492443. http://books.google.com/?id=OA7L1l6oHAYC&pg=PR15.
^ McKetta, John J. (1989). "Nitrobenzene and Nitrotoluene". Encyclopedia of Chemical Processing and Design: Volume 31 – Natural Gas Liquids and Natural Gasoline to Offshore Process Piping: High Performance Alloys. CRC Press. pp. 166–167. ISBN 9780824724818. http://books.google.com/?id=BiywGdlot9kC&pg=PA167.
^ Wildermuth, Egon; Stark, Hans; Friedrich, Gabriele; Ebenhöch, Franz Ludwig; Kühborth, Brigitte; Silver, Jack; Rituper, Rafael (2000). Iron Compounds. doi:10.1002/14356007.a14_591.
^ Lippard, S. J.; Berg, J. M. (1994). Principles of Bioinorganic Chemistry. Mill Valley: University Science Books. ISBN 0-935702-73-3.
^ Food Standards Agency – Eat well, be well – Iron deficiency
^ Sesink, Aloys L. A.; T; K; V (1999). "Red meat and colon cancer: the cytotoxic and hyperproliferative effects of dietary heme". Cancer Research 59 (22): 5704. PMID 10582688. http://cancerres.aacrjournals.org/cgi/content/abstract/59/22/5704.
^ Glei, M.; Klenow, S.; Sauer, J.; Wegewitz, U.; Richter, K.; Pool-Zobel, B. L. (2006). "Hemoglobin and hemin induce DNA damage in human colon tumor cells HT29 clone 19A and in primary human colonocytes". Mutat. Res. 594 (1–2): 162–171. doi:10.1016/j.mrfmmm.2005.08.006. PMID 16226281.
^ Sandhu, M. S.; White, I. R.; McPherson, K. (2001). "Systematic Review of the Prospective Cohort Studies on Meat Consumption and Colorectal Cancer Risk: A Meta-Analytical Approach". Cancer Epidemiology, Biomarkers & Prevention 10 (5): 439. PMID 11352852. http://cebp.aacrjournals.org/content/10/5/439.full.
^ "Eating Red Meat Will Not Increase Colorectal Cancer Risk, Study Suggests". ScienceDaily. June 13, 2007. http://www.sciencedaily.com/releases/2007/06/070611113729.htm. Retrieved 2010-05-23.
^ Hoppe, M.; Hulthén, L.; Hallberg, L. (2005). "The relative bioavailability in humans of elemental iron powders for use in food fortification". European Journal of Nutrition 45 (1): 37–44. doi:10.1007/s00394-005-0560-0. PMID 15864409.
^ Pineda, O.; Ashmead, H. D. (2001). "Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate". Nutrition 17 (5): 381–4. doi:10.1016/S0899-9007(01)00519-6. PMID 11377130.
^ Ashmead, H. DeWayne (1989). Conversations on Chelation and Mineral Nutrition. Keats Publishing. ISBN 0-87983-501-X.
^ "Dietary Reference Intakes: Elements" (PDF). The National Academies. 2001. http://www.iom.edu/Object.File/Master/7/294/0.pdf. Retrieved 2008-05-21.
^ "Iron Deficiency Anemia" (web page). MediResource. http://bodyandhealth.canada.com/condition_info_details.asp?disease_id=274. Retrieved 2008-12-17.
^ Milman, N (1996). "Serum ferritin in Danes: studies of iron status from infancy to old age, during blood donation and pregnancy". International journal of hematology 63 (2): 103–35. doi:10.1016/0925-5710(95)00426-2. PMID 8867722.
^ Rouault, Tracey A. (2003). "How Mammals Acquire and Distribute Iron Needed for Oxygen-Based Metabolism". PLoS Biology 1 (1): e9. doi:10.1371/journal.pbio.0000079. PMC 212690. PMID 14551907. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=212690.
^ Nanami, M.; Ookawara, T; Otaki, Y; Ito, K; Moriguchi, R; Miyagawa, K; Hasuike, Y; Izumi, M et al. (2005). "Tumor necrosis factor-α-induced iron sequestration and oxidative stress in human endothelial cells". Arteriosclerosis, thrombosis, and vascular biology 25 (12): 2495–2501. doi:10.1161/01.ATV.0000190610.63878.20. PMID 16224057. http://cat.inist.fr/?aModele=afficheN&cpsidt=17328512.
^ Neilands, JB (1995). "Siderophores: structure and function of microbial iron transport compounds". The Journal of biological chemistry 270 (45): 26723–6. doi:10.1074/jbc.270.45.26723. PMID 7592901. http://www.jbc.org/content/270/45/26723.short.
^ Neilands, J B (1981). "Microbial Iron Compounds". Annual Review of Biochemistry 50: 715–31. doi:10.1146/annurev.bi.50.070181.003435. PMID 6455965.
^ Boukhalfa, Hakim; Crumbliss, Alvin L. (2002). "Chemical aspects of siderophore mediated iron transport". BioMetals 15 (4): 325–39. doi:10.1023/A:1020218608266. PMID 12405526.
^ Kumar, Vinay; Abbas, Abul K; Fausto, Nelson (2005). "Anemia". Robbins and Cotran: Pathologic Basis of Disease, 7th edition. Elsevier Saunders. http://www.mdconsult.com/das/book/body/90234262-4/0/1249/121.html. Retrieved 2008-03-14.
^ Durupt, S; Durieu, I; Nové-Josserand, R; Bencharif, L; Rousset, H; Vital Durand, D (2000). "Hereditary hemochromatosis". Rev Med Interne 21 (11): 961–71. doi:10.1016/S0248-8663(00)00252-6. PMID 11109593.
^ Brar, S; Henderson, D; Schenck, J; Zimmerman, EA (2009). "Iron accumulation in the substantia nigra of patients with Alzheimer disease and parkinsonism". Archives of neurology 66 (3): 371–4. doi:10.1001/archneurol.2008.586. PMID 19273756. http://archneur.highwire.org/cgi/content/abstract/66/3/371.
^ ^a ^b Cheney, K.; Gumbiner, C.; Benson, B.; Tenenbein, M. (1995). "Survival after a severe iron poisoning treated with intermittent infusions of deferoxamine". J Toxicol Clin Toxicol 33 (1): 61–6. doi:10.3109/15563659509020217. PMID 7837315.
^ ^a ^b "Toxicity, Iron". Medscape. http://www.emedicine.com/emerg/topic285.htm. Retrieved 2010-05-23.
^ Tenenbein, M (1996). "Benefits of parenteral deferoxamine for acute iron poisoning". J Toxicol Clin Toxicol 34 (5): 485–489. doi:10.3109/15563659609028005. PMID 8800185.

Books

H. R. Schubert, History of the British Iron and Steel Industry ... to 1775 AD (Routledge, London, 1957)
R. F. Tylecote, History of Metallurgy (Institute of Materials, London 1992).
R. F. Tylecote, 'Iron in the Industrial Revolution' in J. Day and R. F. Tylecote, The Industrial Revolution in Metals (Institute of Materials 1991), 200–60.
Weeks, Mary Elvira; Leichester, Henry M. (1968). "Elements Known to the Ancients". Discovery of the Elements. Easton, PA: Journal of Chemical Education. pp. 29–40. ISBN 0766138720. LCCCN 68-15217.

External links

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v · d · e Iron compounds

FeBr₂ · FeBr₃ · FeCl₂ · FeCl₃ · FeF₂ · FeF₃ · Fe(NO₃)₃ · FeO · FeO(OH) · Fe(OH)₂ · FePO₄ · FeS · FeSO₄ · Fe₂(CrO₄)₃ · Fe₂O₃ · Fe₂(SO₄)₃ · Fe₃O₄ · Fe₃S₄ · Fe₃(PO₄)₂

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Biology and pharmacology of chemical elements
Dietary minerals
Iron
Chemical elements
Transition metals
Ferromagnetic materials
Building materials
Pyrotechnic fuels
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iron(II) — iron(II) … English syllables
Iron — I ron ([imac] [u^]rn), a. [AS. [=i]ren, [=i]sen. See {Iron}, n.] [1913 Webster] 1. Of, or made of iron; consisting of iron; as, an iron bar, dust. [1913 Webster] 2. Resembling iron in color; as, iron blackness. [1913 Webster] 3. Like iron in… … The Collaborative International Dictionary of English
Iron — I ron ([imac] [u^]rn), n. [OE. iren, AS. [=i]ren, [=i]sen, [=i]sern; akin to D. ijzer, OS. [=i]sarn, OHG. [=i]sarn, [=i]san, G. eisen, Icel. [=i]sarn, j[=a]rn, Sw. & Dan. jern, and perh. to E. ice; cf. Ir. iarann, W. haiarn, Armor. houarn.] [1913 … The Collaborative International Dictionary of English
iron — [ī′ərn] n. [ME iren < OE (chiefly poetic & prob. dissimilated), var. of isern, isen akin to Goth eisarn) < Gmc * īsarna, akin to early Celt * isarno, prob. via Illyrian * eisarno < IE base * eis , to move vigorously; strong, holy (>… … English World dictionary
Iron — bezeichnet eine Gemeinde im französischen Département Aisne, siehe: Iron (Aisne) einen Fluss in Frankreich, Nebenfluss des Noirrieu, siehe: Iron (Fluss) ein Album der finnischen Band Ensiferum, siehe: Iron (Album) SRWare Iron, einen Webbrowser… … Deutsch Wikipedia
IRON — Iron ore deposits occur in Anatolia and northwest Iran. The metalwas probably first worked as a by product of coppersmelting, and rare small iron objects have been found in Mesopotamian graves since the fourth millennium B.C. Iron was worked… … Historical Dictionary of Mesopotamia
iron — ► NOUN 1) a strong, hard magnetic silvery grey metal, used in construction and manufacturing. 2) a tool or implement made of iron. 3) a hand held implement with a flat heated steel base, used to smooth clothes and linen. 4) a golf club used for… … English terms dictionary
Iron — I ron, v. t. [imp. & p. p. {Ironed}; p. pr. & vb. n. {Ironing}.] [1913 Webster] 1. To smooth with an instrument of iron; especially, to smooth, as cloth, with a heated flatiron; sometimes used with out. [1913 Webster] 2. To shackle with irons; to … The Collaborative International Dictionary of English
Iron-on — Iron ons are images that can be imprinted on fabric. They are frequently used to print onto T shirts.On one side is paper, and on the other is the image that will be transferred in reverse. After placing it on the fabric and either running over… … Wikipedia
iron-on — (adj.) 1959, from IRON (Cf. iron) (v.) + ON (Cf. on) … Etymology dictionary
iron — [adj] hard, tough; inflexible adamant, adamantine, cruel, dense, ferric, ferrous, firm, heavy, immovable, implacable, indomitable, inexorable, insensible, obdurate, relentless, rigid, robust, steel, steely, strong, stubborn, thick, unbending,… … New thesaurus

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