| Iron - Fe
CAS: 7439-89-6 Description: Silvery-white metal Classification: Transition Metal Date of Discovery: Known to the ancients Discoverer: Unknown Name Origin: Anglo-Saxon, iron Symbol Origin: Latin ferrum, "iron" |
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Atomic Number: 26
Number of Neutrons: 30 Atomic Mass: 55.845(2) amu Melting Point: 1538 °C Boiling Point: 2861 °C Density (293 K): 7.874 g/cm3 Atomic volume: 7.1 cm3/mol Electrical resistivity: 0.0993 10-6/cm 
Thermal conductivity: 0.802 W/cmK Enthalpy of atomization: 414.2 (est.) Enthalpy of vaporization: 349.60 kJ/mol Enthalpy of fusion: 13.80 kJ/mol Specific heat capacity: 0.44 J/gK |
Energy levels: 2-8-14-2
Electron configuration: [Ar]3d64s2 Crystal Structure: Cubic body centered Atomic radius: 1.72 Å Covalent radius: 1.17 Å Oxidation States: +2, +3, +4, +6 Electronegativity, Pauling: 1.83 Electron affinity: 0.151 eV First ionization energy: 7.870 eV 2nd ionization energy: 16.18 eV 3rd ionization energy: 30.651 eV Polarizability: 8.4 10-24cm3 |
| Isotope | Natural Abundance | Atomic Mass | Half-life | Decay Mode | Spin |
| 46Fe | 46.0008 |  0.02 s |
 + |
||
| 47Fe | 46.9929 | 0.03 s |
+ |
||
| 48Fe | 47.9806 | + |
|||
| 49Fe | 48.9763 | 0.08 s | + |
(7/2-) | |
| 50Fe | 49.9630 | 0.15 s | + |
||
| 51Fe | 50.95683 | 0.31 s | + |
(5/2-) | |
| 52mFe | 46 s | + |
(12+) | ||
| 52Fe | 51.94812 | 8.28 h | +; EC; IT |
0+ | |
| 53mFe | 2.6 m | IT | 19/2- | ||
| 53Fe | 52.945312 | 8.51 m | + |
7/2- | |
| 54Fe | 5.845(35) | 53.939615 | Stable | 0+ | |
| 55Fe | 54.938298 | 2.73 y | - |
3/2- | |
| 56Fe | 91.754 | 55.934942 | Stable | 0+ | |
| 57Fe | 2.119(10) | 56.935398 | Stable | 1/2- | |
| 58Fe | 0.282(4) | 57.933280 | Stable | 0+ | |
| 59Fe | 58.934880 | 44.51 | - |
3/2- | |
| 60Fe | 59.934077 | 1.5 x 106 y | - |
0+ | |
| 61Fe | 60.93675 | 6.0 m | - |
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| 62Fe | 61.93677 | 68 s | - |
0+ | |
| 63Fe | 62.9404 | 6 s | - |
5/2- | |
| 64Fe | 63.9411 | 2.0 s | - |
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| 65Fe | 64.9449 | 0.45 s |
- |
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| 66Fe | 65.9460 | - |
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| 67Fe | 66.9500 | - |
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| 68Fe | 67.953 | - |
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| 69Fe | |||||
The use of iron is prehistoric. Genesis mentions that Tubal-Cain, seven generations from Adam, was "an instructor of every artificer in brass and iron." A remarkable iron pillar, dating to about A.D. 400, remains standing today in Delhi, India. this solid shaft of wrought iron is about 7¼ m high by 40 cm in diameter. Corrosion to the pillar has been minimal although it has been exposed to the weather since its erection. Iron is a relatively abundant element in the universe. It is found in the sun and many types of stars in considerable quantity. Its nuclei are very stable. Iron is found native as a principal component of a class of meteorites known as siderites, and is a minor constituent of the other two classes. The core of the earth, 2150 miles in radius, is thought to be largely composed of iron with about 10% occluded hydrogen. The metal is the fourth most abundant element, by weight, making up the crust of the earth. The most common ore is hematite (Fe2O3), which is frequently seen as black sands along beaches and banks of
streams. Taconite is becoming increasingly important as a commercial ore. Common
iron is a mixture of four isotopes. Ten other isotopes are known to exist. Iron is a
vital constituent of plant and animal life, and appears in hemoglobin. The pure metal
is not often encountered in commerce, but is usually allowed with carbon or other
metals. The pure metal is very reactive chemically and rapidly corrodes, especially
in moist air or at elevated temperatures. It has four allotropic forms or ferrites,
known as alpha ( ), beta (), gamma ( ), and delta ( ), with transition points at 700, 928, and 1530 °C. The form is magnetic, but when transformed into the form, the magnetism disappears although the lattice remains unchanged. The relations of these forms are peculiar. Pig iron is an alloy containing about 3% carbon with varying amounts of S, Si, Mn, and P. It is hard, brittle, fairly fusible, and is used to produce other alloys, including steel. Wrought iron contains only a few tenths of a percent of carbon, is tough malleable, less fusible, and has usually a "fibrous" structure. Carbon steel is an alloy of iron with carbon, with small amounts of Mn, S, P, and Si. Alloy steels are carbon steels with other additives such as nickel, chromium, vanadium, etc. Iron is the cheapest and most abundant, useful, and important of all metals. Natural iron contains four isotopes and isomers. Twenty-one other isotopes and isomers, all radioactive, are now recognized.
LINKS: American Iron and Steel Institute CDC's Nutrition and Physical Activity - Anemia and Iron Iron Deficiency in Children: Who is at risk? ISSource - home page of the Iron & Steel Society Taconite - What is It? Return
Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998. |
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