Iron Fe
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GRU-V® UV Air Disinfection Device from Iron Fe uses UV-C Germicidal Light, a proven technology used to reduce and control the spread of infection and provide cleaner and improved air quality. Especially useful during the current Covid-19 pandemic. Iron Iron is a chemical element with symbol Fe and atomic number 26. Classified as a transition metal, Iron is a solid at room temperature. Slow Fe is the #1 Doctor Recommended iron supplement for iron deficiency.† It features a special controlled release system, so you get the high potency iron you need, with the gentleness you want. Plus, it’s easy to swallow, and gives you less nausea and abdominal discomfort when compared to immediate release iron tablets.
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Alternative Titles: Fe, ferrum
Iron (Fe), chemical element, metal of Group 8 (VIIIb) of the periodic table, the most-used and cheapest metal.
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Element Propertiesatomic number26atomic weight55.847melting point1,538 °C (2,800 °F)boiling point3,000 °C (5,432 °F)specific gravity7.86 (20 °C)oxidation states+2, +3, +4, +6electron configuration[Ar]3d64s2
Occurrence, uses, and properties
Iron makes up 5 percent of Earth’s crust and is second in abundance to aluminum among the metals and fourth in abundance behind oxygen, silicon, and aluminum among the elements. Iron, which is the chief constituent of Earth’s core, is the most abundant element in Earth as a whole (about 35 percent) and is relatively plentiful in the Sun and other stars. In the crust the free metal is rare, occurring as terrestrial iron (alloyed with 2–3 percent nickel) in basaltic rocks in Greenland and carbonaceoussediments in the United States (Missouri) and as a low-nickel meteoric iron (5–7 percent nickel), kamacite. Nickel-iron, a native alloy, occurs in terrestrial deposits (21–64 percent iron, 77–34 percent nickel) and in meteorites as taenite (62–75 percent iron, 37–24 percent nickel). (For mineralogical properties of native iron and nickel-iron, seenative elements [table].) Meteorites are classified as iron, iron-stone, or stony according to the relative proportion of their iron and silicate-mineral content. Iron is also found combined with other elements in hundreds of minerals; of greatest importance as iron ore are hematite (ferric oxide, Fe2O3), magnetite (triiron tetroxide, Fe3O4), limonite (hydrated ferric oxide hydroxide, FeO(OH)∙nH2O), and siderite (ferrous carbonate, FeCO3). Igneous rocks average about 5 percent iron content. The metal is extracted by smelting with carbon (coke) and limestone. (For specific information on the mining and production of iron, seeiron processing.)
Iron orecountrymine production 2006 (metric tons)*% of world mine productiondemonstrated reserves 2006 (metric tons)*, **% of world demonstrated reserves*Estimated.**Iron content.***Detail does not add to total given because of rounding.Source: U.S. Department of the Interior, Mineral Commodity Summaries 2007.China520,000,00030.815,000,000,0008.3Brazil300,000,00017.841,000,000,00022.8Australia270,000,00016.025,000,000,00013.9India150,000,0008.96,200,000,0003.4Russia105,000,0006.231,000,000,00017.2Ukraine73,000,0004.320,000,000,00011.1United States54,000,0003.24,600,000,0002.6South Africa40,000,0002.41,500,000,0000.8Canada33,000,0002.02,500,000,0001.4Sweden24,000,0001.45,000,000,0002.8Iran20,000,0001.21,500,000,0000.8Venezuela20,000,0001.23,600,000,0002.0Kazakhstan15,000,0000.97,400,000,0004.1Mauritania11,000,0000.71,000,000,0000.6Mexico13,000,0000.8900,000,0000.5other countries43,000,0002.517,000,000,0009.4world total1,690,000,000100***180,000,000,000100***
The average quantity of iron in the human body is about 4.5 grams (about 0.004 percent), of which approximately 65 percent is in the form of hemoglobin, which transports molecular oxygen from the lungs throughout the body; 1 percent in the various enzymes that control intracellular oxidation; and most of the rest stored in the body (liver, spleen, bone marrow) for future conversion to hemoglobin. Red meat, egg yolk, carrots, fruit, whole wheat, and green vegetables contribute most of the 10–20 milligrams of iron required each day by the average adult. For the treatment of hypochromic anemias (caused by iron deficiency), any of a large number of organic or inorganic iron (usually ferrous) compounds are used.
Iron, as commonly available, nearly always contains small amounts of carbon, which are picked up from the coke during smelting. These modify its properties, from hard and brittle cast irons containing up to 4 percent carbon to more malleable low-carbon steels containing less than 0.1 percent carbon.
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Three true allotropes of iron in its pure form occur. Delta iron, characterized by a body-centred cubic crystal structure, is stable above a temperature of 1,390 °C (2,534 °F). Below this temperature there is a transition to gamma iron, which has a face-centred cubic (or cubic close-packed) structure and is paramagnetic (capable of being only weakly magnetized and only as long as the magnetizing field is present); its ability to form solid solutions with carbon is important in steelmaking. At 910 °C (1,670 °F) there is a transition to paramagnetic alpha iron, which is also body-centred cubic in structure. Below 773 °C (1,423 °F), alpha iron becomes ferromagnetic (i.e., capable of being permanently magnetized), indicating a change in electronic structure but no change in crystal structure. Above 773 °C (its Curie point), it loses its ferromagnetism altogether. Alpha iron is a soft, ductile, lustrous, gray-white metal of high tensile strength.
Pure iron is quite reactive. In a very finely divided state metallic iron is pyrophoric (i.e., it ignites spontaneously). It combines vigorously with chlorine on mild heating and also with a variety of other nonmetals, including all of the halogens, sulfur, phosphorus, boron, carbon, and silicon (the carbide and silicide phases play major roles in the technical metallurgy of iron). Metallic iron dissolves readily in dilute mineral acids. With nonoxidizing acids and in the absence of air, iron in the +2 oxidation state is obtained. With air present or when warm dilute nitric acid is used, some of the iron goes into solution as the Fe3+ ion. Very strongly oxidizing mediums — for example, concentrated nitric acid or acids containing dichromate — passivate iron (i.e., cause it to lose its normal chemical activity), however, much as they do chromium. Air-free water and dilute air-free hydroxides have little effect on the metal, but it is attacked by hot concentrated sodium hydroxide.
Natural iron is a mixture of four stable isotopes: iron-56 (91.66 percent), iron-54 (5.82 percent), iron-57 (2.19 percent), and iron-58 (0.33 percent).
Iron compounds are amenable to study by taking advantage of a phenomenon known as the Mössbauer effect (the phenomenon of a gamma ray being absorbed and reradiated by a nucleus without recoil). Although the Mössbauer effect has been observed for about one-third of the elements, it is particularly for iron (and to a lesser extent tin) that the effect has been a major research tool for the chemist. In the case of iron the effect depends on the fact that the nucleus of iron-57 can be excited to a high energy state by the absorption of gamma radiation of very sharply defined frequency that is influenced by the oxidation state, electron configuration, and chemical environment of the iron atom and can thus be used as a probe of its chemical behaviour. The marked Mössbauer effect of iron-57 has been used in studying magnetism and hemoglobin derivatives and for making a very precise nuclear clock.
Quick Facts
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Element Iron — Fe
Comprehensive data on the chemical element Iron is provided on this page; including scores of properties, element names in many languages, most known nuclides of Iron. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one’s studies.
Iron Menu
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Overview of Iron
- Atomic Number: 26
- Group: 8
- Period: 4
- Series: Transition Metals
Iron’s Name in Other Languages
- Latin: Ferrum
- Czech: Železo
- Croatian: Željezo
- French: Fer
- German: Eisen — s
- Italian: Ferro
- Norwegian: Jern
- Portuguese: Ferro
- Russian: Железо
- Spanish: Hierro
- Swedish: Järn
Atomic Structure of Iron
- Atomic Radius: 1.72Å
- Atomic Volume: 7.1cm3/mol
- Covalent Radius: 1.17Å
- Cross Section (Thermal Neutron Capture)σa/barns: 2.56
- Crystal Structure: Cubic body centered
- Electron Configuration:1s2 2s2p6 3s2p6d6 4s2
- Electrons per Energy Level: 2,8,14,2Shell Model
- Ionic Radius: 0.645Å
- Filling Orbital: 3d6
- Number of Electrons (with no charge): 26
- Number of Neutrons (most common/stable nuclide): 30
- Number of Protons: 26
- Oxidation States: 2,3
- Valence Electrons: 3d6 4s2Electron Dot Model
Chemical Properties of Iron
- Electrochemical Equivalent: 0.69455g/amp-hr
- Electron Work Function: 4.7eV
- Electronegativity: 1.83 (Pauling); 1.64 (Allrod Rochow)
- Heat of Fusion: 13.8kJ/mol
- Incompatibilities:
- Ionization Potential
- First: 7.87
- Second: 16.18
- Third: 30.651
- Valence Electron Potential (-eV): 67
Physical Properties of Iron
- Atomic Mass Average: 55.847
- Boiling Point: 3023K 2750°C 4982°F
- Coefficient of lineal thermal expansion/K-1: 12.3E-6
- ConductivityElectrical: 0.0993 106/cm Ω
Thermal: 0.802 W/cmK - Density: 7.874g/cc @ 300K
- Description:Pure iron is lustrous, silvery and easy to work. Iron easily rusts in damp air.
- Elastic Modulus:
- Bulk: 170/GPa
- Rigidity: 82/GPa
- Youngs: 211/GPa
- Enthalpy of Atomization: 414.2 kJ/mole @ 25°C
- Enthalpy of Fusion: 14.9 kJ/mole
- Enthalpy of Vaporization: 351 kJ/mole
- Flammablity Class:
- Freezing Point:see melting point
- Hardness Scale
- Brinell: 490 MN m-2
- Mohs: 4
- Vickers: 608 MN m-2
- Heat of Vaporization: 349.6kJ/mol
- Melting Point: 1808K 1535°C 2795°F
- Molar Volume: 7.11 cm3/mole
- Optical Reflectivity: 65%
- Physical State (at 20°C & 1atm): Solid
- Specific Heat: 0.44J/gK
- Vapor Pressure = 7.05Pa@1535°C
Regulatory / Health
- CAS Number
- 7439–89–6
- OSHAPermissible Exposure Limit (PEL)
- No limits set by OSHA
- OSHA PEL Vacated 1989
- No limits set by OSHA
- NIOSHRecommended Exposure Limit (REL)
- No limits set by NIOSH
- Levels In Humans:
Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances. - Blood/mg dm-3: 447
- Bone/p.p.m: 3–380
- Liver/p.p.m: 250–1400
- Muscle/p.p.m: 180
- Daily Dietary Intake: 6–40 mg
- Total Mass In Avg. 70kg human: 4.2 g
- Discovery Year: Unknown
- Name Origin:Latin, ferrum; Anglo-Saxon, iron
- Abundance of Iron:
- Earth’s Crust/p.p.m.: 41000
- Seawater/p.p.m.:
- Atlantic Suface: 0.0001
- Atlantic Deep: 0.0004
- Pacific Surface: 0.00001
- Pacific Deep: 0.0001
- Atmosphere/p.p.m.: N/A
- Sun (Relative to H=1E12): 3.16E+07
- Sources of Iron:Obtained from hematite, magnetite, goethite, lepidocrocite and siderite. Annual world production is around 716,000,000 tons. Primary areas iron is mined are USA, Canada, Sweden, South Africa, Russia, India and Japan.
- Uses of Iron:Used in steel and other alloys which are used in countless products. It is essential for animals as it is the chief constituent of hemoglobin which carries oxygen in blood vessels. Iron is the most important element of all the metals.
- Additional Notes:Deficiency of iron leads to anaemia, but excess iron in the body causes liver and kidney damage.
Iron Menu
- Iron Page One
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References
A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page.
Related Resources
- Anatomy of the Atom
Answers many questions regarding the structure of atoms. - Molarity, Molality and Normality
Introduces stoichiometry and explains the differences between molarity, molality and normality. - Molar Mass Calculations and Javascript Calculator
Molar mass calculations are explained and there is a JavaScript calculator to aid calculations. - Chemical Database
This database focuses on the most common chemical compounds used in the home and industry.
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