Difference between revisions of "Zirconium"
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Revision as of 19:40, 28 April 2018
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Zirconium, Zr | ||||
| Appearance | Silvery white metal | ||||
| Zirconium in the periodic table | |||||
| |||||
| Atomic number | 40 | ||||
| Standard atomic weight (Ar) | 91.224(2) | ||||
| Group, block | , d-block | ||||
| Period | period 5 | ||||
| Electron configuration | [Kr] 4d2 5s2 | ||||
per shell | 2, 8, 18, 10, 2 | ||||
| Physical properties | |||||
| Silvery-white | |||||
| Phase | Solid | ||||
| Melting point | 2128 K (1855 °C, 3371 °F) | ||||
| Boiling point | 4650 K (4377 °C, 7911 °F) | ||||
| Density near r.t. | 6.52 g/cm3 | ||||
| when liquid, at | 5.8 g/cm3 | ||||
| Heat of fusion | 14 kJ/mol | ||||
| Heat of | 591 kJ/mol | ||||
| Molar heat capacity | 25.36 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 4, 3, 2, 1, −2 (an amphoteric oxide) | ||||
| Electronegativity | Pauling scale: 1.33 | ||||
| energies |
1st: 640.1 kJ/mol 2nd: 1270 kJ/mol 3rd: 2218 kJ/mol | ||||
| Atomic radius | empirical: 160 pm | ||||
| Covalent radius | 175±7 pm | ||||
| Miscellanea | |||||
| Crystal structure | hexagonal close-packed (hcp) | ||||
| Speed of sound thin rod | 3800 m/s (at 20 °C) | ||||
| Thermal expansion | 5.7 µm/(m·K) | ||||
| Thermal conductivity | 22.6 W/(m·K) | ||||
| Electrical resistivity | 421 Ω·m (at 20 °C) | ||||
| Magnetic ordering | Paramagnetic | ||||
| Young's modulus | 88 GPa | ||||
| Shear modulus | 33 GPa | ||||
| Bulk modulus | 91.1 GPa | ||||
| Poisson ratio | 0.34 | ||||
| Mohs hardness | 5.0 | ||||
| Vickers hardness | 820–1800 MPa | ||||
| Brinell hardness | 638–1880 MPa | ||||
| CAS Registry Number | 7440-67-7 | ||||
| History | |||||
| Naming | after zircon, zargun زرگون meaning "gold-colored". | ||||
| Discovery | Martin Heinrich Klaproth (1789) | ||||
| First isolation | Jöns Jakob Berzelius (1824) | ||||
Zirconium is a chemical element with symbol Zr and atomic number 40. The name of zirconium comes from the name of the mineral zircon, the most important source of zirconium.
Contents
Properties
Chemical
Zirconium is highly resistant to corrosion by alkalis, acids, salt water and other agents, though it will dissolve in hydrochloric acid and sulfuric acid more quickly in the presence of fluorine.
Zirconium powder is highly flammable and will burn with an intense white flame.
The most used zirconium compound is probably zirconyl chloride[1].
Physical
Zirconium is a lustrous, greyish-white, soft, ductile and malleable metal when pure. It is brittle and hard to work with when impure, behavior also observed in tungsten. In powder form, zirconium is highly flammable, but the solid form is far less prone to ignition. Alloys with zinc become magnetic below 35 K.
Zirconium's melting point is 1855 °C (3371 °F), and its boiling point is 4371 °C (7900 °F). Zirconium is lighter than iron, with a density of 6.52 g/cm3.
Natural zirconium always contains a few w% of Hafnium (Z = 72), an element it is chemically almost indistinguishable from. For nuclear applications zirconium needs to be de-hafnified to reduce neutron absorptivity.
Availability
Zirconium is sold by various chemical suppliers. It can also be found of eBay and Amazon.
Zirconium vodka shot glasses are an interesting source of zirconium metal, though it's a waste to scrap them for zirconium metal.
Zirconia (ZrO2) and other Zr compounds can be prepared from pottery Zircon relatively easily [2].
Isolation
Zirconium metal can be extracted by reducing zirconium tetrachloride with magnesium metal, in an inert atmosphere or in vacuum.
- ZrCl4 + 2 Mg → Zr + 2 MgCl2
The resulting zirconium sponge is purified by dissolving the magnesium halide in water.
Other metals such as calcium can also be used.
Projects
- Make white fire
- Flash powder
Handling
Safety
Zirconium has very low toxicity. Zinc powder can be a serious fire hazard if ignited.
Storage
Bulk zirconium metal doesn't require special storage, and can be stored in any container. Zirconium powder should be stored in closed containers, away from any flame.
Disposal
It's best to try to recycle zirconium than throwing it away.
