Zirconium

Zirconium, ₄₀Zr

Zirconium
Pronunciation	/zɜːrˈkoʊniəm/ ​(zur-KOH-nee-əm)
Appearance	silvery white
Standard atomic weight Ar°(Zr)
	91.222±0.003[1] 91.222±0.003 (abridged)[2]
Zirconium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Ti ↑ Zr ↓ Hf yttrium ← zirconium → niobium
Atomic number (Z)	40
Group	group 4
Period	period 5
Block	d-block
Electron configuration	[Kr] 4d2 5s2
Electrons per shell	2, 8, 18, 10, 2
Physical properties
Phase at STP	solid
Melting point	2125 K ​(1852 °C, ​3365 °F)
Boiling point	4650 K ​(4377 °C, ​7911 °F)
Density (at 20° C)	6.505 g/cm3[3]
when liquid (at m.p.)	5.8 g/cm3
Heat of fusion	14 kJ/mol
Heat of vaporization	591 kJ/mol
Molar heat capacity	25.36 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2639 2891 3197 3575 4053 4678
Atomic properties
Oxidation states	common: +4 +1,[4] +2,[5][6] +3[4]
Electronegativity	Pauling scale: 1.33
Ionization energies	1st: 640.1 kJ/mol 2nd: 1270 kJ/mol 3rd: 2218 kJ/mol
Atomic radius	empirical: 160 pm
Covalent radius	175±7 pm
Spectral lines of zirconium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 323.22 pm c = 514.79 pm (at 20 °C)[3]
Thermal expansion	5.69×10−6/K (at 20 °C)[3][a]
Thermal conductivity	22.6 W/(m⋅K)
Electrical resistivity	421 nΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic[7]
Young's modulus	88 GPa
Shear modulus	33 GPa
Bulk modulus	91.1 GPa
Speed of sound thin rod	3800 m/s (at 20 °C)
Poisson ratio	0.34
Mohs hardness	5.0
Vickers hardness	820–1800 MPa
Brinell hardness	638–1880 MPa
CAS Number	7440-67-7
History
Naming	after zircon, zargun زرگون meaning "gold-colored".
Discovery	Martin Heinrich Klaproth (1789)
First isolation	Jöns Jakob Berzelius (1824)
Isotopes of zirconium v e
Main isotopes[8] Decay abun­dance half-life (t1/2) mode pro­duct 88Zr synth 83.4 d ε 88Y γ – 89Zr synth 78.4 h ε 89Y β+ 89Y γ – 90Zr 51.5% stable 91Zr 11.2% stable 92Zr 17.1% stable 93Zr trace 1.53×106 y β− 93Nb 94Zr 17.4% stable 96Zr 2.80% 2.34×1019 y β−β− 96Mo
Category: Zirconium view talk edit | references

Zirconium is a chemical element; it has symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyish-white color that closely resembles hafnium and, to a lesser extent, titanium. It is solid at room temperature, ductile, malleable and corrosion-resistant. The name zirconium is derived from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian zargun (zircon; zar-gun, "gold-like" or "as gold").^[9] Besides zircon, zirconium occurs in over 140 other minerals, including baddeleyite and eudialyte; most zirconium is produced as a byproduct of minerals mined for titanium and tin.

Zirconium forms a variety of inorganic compounds, such as zirconium dioxide, and organometallic compounds, such as zirconocene dichloride. Five isotopes occur naturally, four of which are stable. The metal and its alloys are mainly used as a refractory and opacifier; pure zirconium plays a vital role in the construction of nuclear reactors due to strong resistance to corrosion and low nuclear reaction cross section, and in space vehicles and turbine blades where high heat resistance is necessary. Zirconium also finds uses in flashbulbs, biomedical applications such as dental implants and prosthetics, deodorant, and water purification systems.

Zirconium compounds have no known biological role, though the element is widely distributed in nature and appears in small quantities in biological systems without adverse effects. There is no indication of zirconium as a carcinogen. The main hazards posed by zirconium are flammability in powder form and irritation of the eyes.

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