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| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | R | S | T | U | V | X | Z | ||
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| Iron | Fer | Željezo | Ferro | Eisen | ||||||||||||||||||||
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Fe Ferrum |
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- Iron has been known since ancient times. The origin of the name comes from the Latin word ferrum meaning iron. It is malleable, ductile, silvery-white metal. Exposed surfaces form red-brown oxides. Forms very strong alloys (steel). Ferromagnetic. Metal dust flammable. Fourth most abundant element in the earth's crust.
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TRANSITION ELEMENT: IRON GROUP | |
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| Relative atomic mass: | 55.845(2) | Electronic configuration: | [Ar] 3d6 4s2 |
| Formal oxidation number: | +2 +3 | Electronegativities: | 1.83 |
| Thermal conductivity: | 80.2 W m-1 K-1 | Electrical resistivity (20 °C): | 9.71 μΩcm |
| Atomic radius: | 124.1 pm | Standard state (20 °C): | solid |
| Density (g dm-3): | 7874 (293 K) 7035 (m.p.) |
Molar volume (cm3 mol-1): | 7.09 (293 K) 7.94 (m.p.) |
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THERMAL PROPERTIES | |
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| Melting point: | 1538 °C | Heat of fusion: | 14.9 kJ mol-1 |
| Boiling point: | 2861 °C | Heat of vaporization: | 340.2 kJ mol-1 |
| Critical temperature: | 5693 °C | Heat of atomization: | 413.96 kJ mol-1 |
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IONIZATION ENERGIES AND ABUNDANCE | |
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| 1st ionization energy: | 762.47 kJ mol-1 | Abundance of element (air): | - ppm |
| 2nd ionization energy: | 1561.90 kJ mol-1 | Abundance of element (Earth's crust): | 70700 ppm |
| 3rd ionization energy: | 2957.49 kJ mol-1 | Abundance of element (oceans): | 0.01 ppm |
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ISOTOPES | |
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Isotopes | Relative atomic mass | Abundance (%) |
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54Fe | 53.939615(1) | 5.8(1) |
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56Fe | 55.934942(1) | 91.72(30) |
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57Fe | 56.935399(1) | 2.1(1) |
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58Fe | 57.933280(1) | 0.28(1) |
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MINERALS AND USES | |
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- Iron is obtained from iron ores. Pure metal produced in blast furnaces by layering limestone, coke and iron ore and forcing hot gasses into the bottom. This heats the coke red hot and the iron is reduced from its oxides and liquefied where it flows to the bottom. Iron is the most common metal in human society. More than 90% of all metal refined in the world is iron. Used in steel and other alloys. It is the chief constituent of hemoglobin which carries oxygen in blood vessels. Its oxides are used in magnetic tapes and disks. The price of 99.97 % pure iron pieces is 53.00 € for 1000 g.
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REDUCTION POTENTIALS | |
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Balanced half-reaction | Eo / V | Annotation |
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Fe3+ + 3e-  Fe(s) |
- 0.04 | |
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Fe3+ + e- Fe2+ |
+0.771 | |
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Fe3+ + e- Fe2+ |
+0.700 | 1 mol dm-3 HCl |
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Fe3+ + e- Fe2+ |
+0.732 | 1 mol dm-3 HClO4 |
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Fe3+ + e- Fe2+ |
+0.68 | 1 mol dm-3 H2SO4 |
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Fe2+ + 2e- Fe(s) |
- 0.440 | |
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FeOH2+ + H+ + e- Fe2+ + H2O |
+0.91 | |
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Fe(OH)2+ + 2H+ + e- Fe2+ + 2H2O |
+1.19 | |
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FeO42- + 8H+ + 3e- Fe3+ + 4H2O |
+1.70 | |
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FeO42- + 7H+ + 3e- FeOH2+ + 3H2O |
+1.65 | |
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FeO42- + 6H+ + 3e- Fe(OH)2+ + 2H2O |
+1.56 | |
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FeO42- + 5H+ + 3e- HFeO2 + 2H2O |
+1.00 | |
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HFeO2- + 3H+ + 2e- Fe(s) + 2H2O |
+0.49 | |
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Fe(CN)63- + e- Fe(CN)64- |
+0.36 | |
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Fe(CN)63- + e- Fe(CN)64- |
+0.71 | 1 mol dm-3 HCl |
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Fe(CN)63- + e- Fe(CN)64- |
+0.72 | 1 mol dm-3 HClO4 |
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Fe(CN)63- + e- Fe(CN)64- |
+0.72 | 1 mol dm-3 H2SO4 |
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Fe(C12H8N2)33+ + e- Fe(C12H8N2)32+ |
+1.06 | |
