Zirconium

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Zirconium,  40Zr
General properties
Name, symbol Zirconium, Zr
Appearance Silvery white metal
Zirconium in the periodic table
Titanium

Zr

Hafnium
YttriumZirconiumNiobium
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)
· references

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.

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.

References

Relevant Sciencemadness threads