|lustrous metallic with a grayish tinge|
Spectral lines of iron
|ឈ្មោះ, និមិត្តសញ្ញា, លេខ||iron, Fe, 26|
|Element category||transition metal|
|ក្រុម, ខួប, block||8, 4, d|
|លេខអេឡិចត្រុង||[Ar] 3d6 4s2|
2, 8, 14, 2
|ដង់ស៊ីតេ (near r.t.)||7.874 g·cm−3|
|ដង់ស៊ីតេអង្គធាតុរាវ នៅ ចំណុចរលាយ||6.98 g·cm−3|
|ចំណុចរលាយ||1811 K, 1538 °C, 2800 °F|
|ចំណុចរំពុះ||3134 K, 2862 °C, 5182 °F|
|Heat of fusion||13.81 kJ·mol−1|
|Heat of vaporization||340 kJ·mol−1|
|Molar heat capacity||25.10 J·mol−1·K−1|
|ចំនួនអុកស៊ីតកម្ម||6, 5, 4, 3, 2, 1, -1, -2|
|អេឡិចត្រូនេកាទីវ||1.83 (Pauling scale)|
|1st: 762.5 kJ·mol−1|
|2nd: 1561.9 kJ·mol−1|
|3rd: 2957 kJ·mol−1|
|Atomic radius||126 pm|
|Covalent radius||132±3 (low spin), 152±6 (high spin) pm|
between 1185–1667 K
|Electrical resistivity||(20 °C) 96.1 nΩ·m|
|Thermal conductivity||80.4 W·m−1·K−1|
|Thermal expansion||(25 °C) 11.8 µm·m−1·K−1|
|Speed of sound (thin rod)||(r.t.) (electrolytic)|
|Young's modulus||211 GPa|
|Shear modulus||82 GPa|
|Bulk modulus||170 GPa|
|Vickers hardness||608 MPa|
|Brinell hardness||490 MPa|
|CAS registry number||7439-89-6|
|Discovery||before 5000 BC|
|Most stable isotopes|
|Main article: Isotopes of iron|
ដែក គឺជាធាតុគីមីមួយដែលមាននិមិត្តសញ្ញា Fe (from ឡាតាំង ៖ 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 the most common isotope of iron) is the last nuclear fusion reaction that is exothermic. This causes radioactive nickel to become the last element to be produced before collapse of a supernova leads to the explosive events that scatter this precursor radionuclide of iron abundantly 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 hydrated iron oxides, commonly 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 copper alloys, which have lower melting temperatures, 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 0.002% 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 pig 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 and the abundance of iron.
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 is ferrocene, 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.
- El Mutún in Bolivia, where 20% of the world's accessible iron is located.
- Iron fertilization – proposed fertilization of oceans to stimulate phytoplankton growth.
- Iron (metaphor)
- Iron in folklore
- List of countries by iron production
- Pelletising – process of creation of iron ore pellets.
- Rustproof iron
- Demazeau, G.; Buffat, B.; Pouchard, M.; Hagenmuller, P. (1982)។ "Recent developments in the field of high oxidation states of transition elements in oxides stabilization of Six-coordinated Iron(V)"។ Zeitschrift für anorganische und allgemeine Chemie 491: 60។ អ.វ.ល.:10.1002/zaac.19824910109។
- Ram, R. S. and Bernath, P. F. (2003)។ "Fourier transform emission spectroscopy of the g4Δ-a4Δ system of FeCl"។ Journal of Molecular Spectroscopy 221 (2): 261។ Bibcode 2003JMoSp.221..261R។ អ.វ.ល.:10.1016/S0022-2852(03)00225-X។ http://bernath.uwaterloo.ca/media/266.pdf។
- Weeks, Mary Elvira; Leichester, Henry M. (1968)។ "Elements Known to the Ancients"។ Discovery of the Elements។ Easton, PA: Journal of Chemical Education។ ទំ. 29–40។ ល.ស.ប.អ. 0-7661-3872-0។ LCCN 68-15217។
- 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.
- It's Elemental – Iron
- The Most Tightly Bound Nuclei
- Chemistry in its element podcast (MP3) from the Royal Society of Chemistry's Chemistry World: Iron
- Iron at The Periodic Table of Videos (University of Nottingham)
- Metallurgy for the non-Metallurgist