Hafnium

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Hafnium,  72Hf
Hf-crystal bar.jpg
General properties
Appearance steel gray
Staundart atomic wecht (Ar, staundart) 178.49(2)
Hafnium in the periodic cairt
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 Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) 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 Mercur (element) Thallium Leid (element) 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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Zr

Hf

Rf
lutetiumhafniumtantalum
Atomic nummer (Z) 72
Group group 4
Period period 6
Block d-block
Electron confeeguration [Xe] 4f14 5d2 6s2
Electrons per shell
2, 8, 18, 32, 10, 2
Pheesical properties
Phase (at STP) solit
Meltin pynt 2506 K ​(2233 °C, ​4051 °F)
Bylin pynt 4876 K ​(4603 °C, ​8317 °F)
Density (near r.t.) 13.31 g/cm3
when liquid (at m.p.) 12 g/cm3
Heat o fusion 27.2 kJ/mol
Heat o vapourisation 571 kJ/mol
Molar heat capacity 25.73 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2689 2954 3277 3679 4194 4876
Atomic properties
Oxidation states 4, 3, 2 (amphoteric oxide)
Electronegativity Pauling scale: 1.3
Atomic radius empirical: 159 pm
Covalent radius 175±10 pm
Color lines in a spectral range
Miscellanea
Creestal structur hexagonal close-packed (hcp)
Hexagonal close packed creestal structur for hafnium
Speed o soond thin rod 3010 m/s (at 20 °C)
Thermal expansion 5.9 µm/(m·K) (at 25 °C)
Thermal conductivity 23.0 W/(m·K)
Electrical resistivity 331 n Ω·m (at 20 °C)
Magnetic orderin paramagnetic[1]
Young's modulus 78 GPa
Shear modulus 30 GPa
Bouk modulus 110 GPa
Poisson ratio 0.37
Mohs haurdness 5.5
Vickers haurdness 1760 MPa
Brinell haurdness 1700 MPa
CAS Nummer 7440-58-6
History
Predeection Dmitri Mendeleev (1869)
Diskivery Dirk Coster an George de Hevesy (1922)
First isolation Dirk Coster an George de Hevesy (1922)
Main isotopes o hafnium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
172Hf syn 1.87 y ε 172Lu
174Hf 0.162% 2×1015 y α 170Yb
176Hf 5.206% - (α) 172Yb
177Hf 18.606% - (α) 173Yb
178Hf 27.297% - (α) 174Yb
178m3Hf syn 31 y IT 178Hf
179Hf 13.629% - (α) 175Yb
180Hf 35.1% - (α) 176Yb
182Hf trace 8.9×106 y β 182Ta
Decay modes in parentheses are predictit, but hae nae yet been observed
| references | in Wikidata

Hafnium is a chemical element wi the seembol Hf an atomic nummer 72. A lustrous, sillery gray, tetravalent transeetion metal, hafnium chemically resembles zirconium an is foond in zirconium minerals. Its existence wis predictit bi Dmitri Mendeleev in 1869. Hafnium wis the penultimate stable isotope element tae be discovered (rhenium wis identified twa years later). Hafnium is named efter Hafnia, the Latin name for Copenhagen, whaur it wis discovered.

References[eedit | eedit soorce]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.