Difference between revisions of "Vanadium"
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==Isolation== | ==Isolation== | ||
| + | In industries is Vanadium metal is obtained via a multistep process that begins with the roasting of crushed ore with NaCl or Na2CO3 at about 850 °C to give sodium metavanadate (NaVO3). An aqueous extract of this solid is acidified to give "red cake", a polyvanadate salt, which is reduced with calcium metal.[[File:Vanadinite.jpg|thumb|right|Vanadinite - one of the main ores of Vanadium (Pb5(VO4)3Cl).]] | ||
Vanadium can be obtained by reducing [[vanadium pentoxide]] with [[aluminium]], [[magnesium]], or [[hydrogen]]. Note that aluminum is soluble in vanadium, so to isolate pure metal one must not use an excess of aluminum. Magnesium does not share this level of solubility in vanadium metal, but the reaction between V<sub>2</sub>O<sub>5</sub> and Mg is sufficiently energetic to boil the V metal produced. | Vanadium can be obtained by reducing [[vanadium pentoxide]] with [[aluminium]], [[magnesium]], or [[hydrogen]]. Note that aluminum is soluble in vanadium, so to isolate pure metal one must not use an excess of aluminum. Magnesium does not share this level of solubility in vanadium metal, but the reaction between V<sub>2</sub>O<sub>5</sub> and Mg is sufficiently energetic to boil the V metal produced. | ||
Revision as of 09:32, 31 January 2016
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Vanadium, V | ||||
| Appearance | Silvery-gray metal | ||||
| Vanadium in the periodic table | |||||
| |||||
| Atomic number | 23 | ||||
| Standard atomic weight (Ar) | 50.9415(1) | ||||
| Group, block | , d-block | ||||
| Period | period 4 | ||||
| Electron configuration | [Ar] 3d3 4s2 | ||||
per shell | 2, 8, 11, 2 | ||||
| Physical properties | |||||
| Silvery-gray | |||||
| Phase | Solid | ||||
| Melting point | 2183 K (1910 °C, 3470 °F) | ||||
| Boiling point | 3680 K (3407 °C, 6165 °F) | ||||
| Density near r.t. | 6.0 g/cm3 | ||||
| when liquid, at | 5.5 g/cm3 | ||||
| Heat of fusion | 21.5 kJ/mol | ||||
| Heat of | 444 kJ/mol | ||||
| Molar heat capacity | 24.89 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | +5, +4, +3, +2, +1, −1, −3 (an amphoteric oxide) | ||||
| Electronegativity | Pauling scale: 1.63 | ||||
| energies |
1st: 650.9 kJ/mol 2nd: 1414 kJ/mol 3rd: 2830 kJ/mol | ||||
| Atomic radius | empirical: 134 pm | ||||
| Covalent radius | 153±8 pm | ||||
| Miscellanea | |||||
| Crystal structure | body-centered cubic (bcc) | ||||
| Speed of sound thin rod | 4560 m/s (at 20 °C) | ||||
| Thermal expansion | 8.4 µm/(m·K) (at 25 °C) | ||||
| Thermal conductivity | 30.7 W/(m·K) | ||||
| Electrical resistivity | 197 Ω·m (at 20 °C) | ||||
| Magnetic ordering | Paramagnetic | ||||
| Young's modulus | 128 GPa | ||||
| Shear modulus | 47 GPa | ||||
| Bulk modulus | 160 GPa | ||||
| Poisson ratio | 0.37 | ||||
| Mohs hardness | 6.7 | ||||
| Vickers hardness | 628–640 MPa | ||||
| Brinell hardness | 600–742 MPa | ||||
| CAS Registry Number | 7440-62-2 | ||||
| History | |||||
| Discovery | Andrés Manuel del Río (1801) | ||||
| First isolation | Nils Gabriel Sefström (1830) | ||||
| Named by | Nils Gabriel Sefström (1830) | ||||
Vanadium is a chemical element with symbol V and atomic number 23. It is mainly used in industry for high strength steels.
Contents
Properties
Chemical
It has good resistance to corrosion and it is stable against alkali and sulfuric and hydrochloric acids.[12] It is oxidized in air at about 933 K (660 °C, 1220 °F), although an oxide layer forms even at room temperature.
Physical
Vanadium is a medium-hard, ductile, malleable, strong silvery-gray or steel-blue metal. Vanadium is harder than most pure metals and common steels. Vanadium has a high melting point of 1910 °C and boils at 3407 °C. Vanadium is lighter than steel, with a density of 6 g/cm3.
Availability
Vanadium is sold by various chemical suppliers.
It can also be extracted from chromium-vanadium steels, generally encountered in tools and other devices. Ferrovanadium is also a source.
Isolation
In industries is Vanadium metal is obtained via a multistep process that begins with the roasting of crushed ore with NaCl or Na2CO3 at about 850 °C to give sodium metavanadate (NaVO3). An aqueous extract of this solid is acidified to give "red cake", a polyvanadate salt, which is reduced with calcium metal.
Vanadium can be obtained by reducing vanadium pentoxide with aluminium, magnesium, or hydrogen. Note that aluminum is soluble in vanadium, so to isolate pure metal one must not use an excess of aluminum. Magnesium does not share this level of solubility in vanadium metal, but the reaction between V2O5 and Mg is sufficiently energetic to boil the V metal produced.
Pure vanadium metal can be obtained through the thermal decomposition of vanadium(III) iodide:
- 2 V + 3 I2 ⇌ 2 VI3
Projects
- Make vanadium pentoxide
- Make various high strength steels
Handling
Safety
Vanadium compounds show toxicity and should be handled with care.
Storage
Vanadium should be stored in closed containers.
Vanadium powder should be stored away from air.
Disposal
Vanadium should be taken to disposal facilities.
References
Elementcollector1: Isolation notes based on experience, feel free to argue.
