Hafnium Elemental Symbol
Hafnium



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Hafnium Hafnium Afnio Háfnio Hafnio Hafnium

Hafnium(Hf) atomic and molecular weight, atomic number and elemental symbol Hafnium is a Block D, Group 4, Period 6 element. Hafnium Bohr ModelThe number of electrons in each of Hafnium's shells is 2, 8, 18, 32, 10, 2 and its electronic configuration is [Xe] 4f14 5d2 6s2. The hafnium atom has a radius of 156.4.pm and its Van der Waals radius is 200.pm. In its elemental form, CAS 7440-58-6, hafnium has a steel gray appearance. Hafnium does not exist as a free element in nature. It is found in zirconium compounds such as zircon (ZrSiO4). Hafnium was first predicted by Dmitri Mendeleev in 1869 but it was not until 1922 that it was first isolated Dirk Coster and George de Hevesy.

Elemental HafniumThere are relatively few technical uses for hafnium and, due to its ability as a nuclear "getter" or absorber of neutrons, much of the hafnium that is produced is used in control rods for nuclear reactors. Hafnium is also used in iron, titanium, niobium, tantalum, and other alloys. Hafnium is replacing polysilicon as the principle gate or electrode material in metal oxide semiconductor field effect transistors (MOSFETs), which are the basis for all modern semiconductors. As semiconductors get smaller, the limiting factor in further size reduction has been the ability of the silicon oxide gate to perform below 10 angstroms where leakage occurs. Recent research has been devoted to the development of High-k materials which can function as a di-electric barrier or gate with lower leakage. Using hafnium based alloys as this di-electric gate has allowed for the development of MOSFET gates smaller than 10 angstroms.This allows for further size reduction, reduced switching power requirements and improved performance. High Purity (99.999%) Hafnium Oxide (HfO2) PowderHafnium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%)Hafnium (Hf) Sputtering TargetElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Hafnium nanoparticles and nanopowders provide ultra-high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Hafnium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Hafnium is not toxic; however, safety data for hafnium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab below.


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Hafnium Properties


GENERAL PROPERTIES   PHYSICAL PROPERTIES  
Symbol: Hf Melting Point: 2506 K, 2233 °C, 4051 °F
Atomic Number: 72 Boiling Point: 4876 K, 4603 °C, 8317 °F
Atomic Weight: 178.49 Density: 13.31 g·cm−3
Element Category: transition metal Liquid Density @ Melting Point: 12 g·cm−3
Group, Period, Block: 4, 6, d Specific Heat: 0.14 (kJ/kg K)
    Heat of Vaporization 570.7 kJ mol-1
CHEMICAL STRUCTURE Heat of Fusion 25.5 kJ mol-1
Electrons: 72 Thermal Conductivity: 23.0 W·m−1·K−1
Protons: 72 Thermal Expansion: (25 °C) 5.9 µm·m−1·K−1
Neutrons: 106 Electrical Resistivity: (20 °C) 331 nΩ·m
Electron Configuration: [Xe] 4f145d26s2 Electronegativity: 1.3 (Pauling scale)
Atomic Radius: 159 pm Tensile Strength: N/A
Covalent Radius: 175±10 pm Molar Heat Capacity: 25.73 J·mol−1·K−1
Van der Waals radius: 200.pm Young's Modulus: 78 GPa
Oxidation States: 4, 3, 2 (amphoteric oxide) Shear Modulus: 30 GPa
Phase: Solid Bulk Modulus: 110 GPa
Crystal Structure: Hexagonal Poisson Ratio: 0.37
Magnetic Ordering: paramagnetic Mohs Hardness: 5.5
1st Ionization Energy: 658.52 kJ mol-1 Vickers Hardness: 1760 MPa
2nd Ionization Energy: 1437.64 kJ mol-1 Brinell Hardness: 1700 MPa
3rd Ionization Energy: 2248.12 kJ mol-1 Speed of Sound: (20 °C) 3010 m·s−1
       
IDENTIFIERS   MISCELLANEOUS  
CAS Number: 7440-58-6 Abundance in typical human body, by weight: N/A
ChemSpider ID: 22422 Abundance in typical human body, by atom: N/A
PubChem CID: 23986 Abundance in universe, by weight: 0.7 ppb
MDL Number: MFCD00011032 Abundance in universe, by atom: 0.005 ppb
EC Number: 231-166-4 Discovered By: Dirk Coster and George de Hevesy
Beilstein Number: N/A Discovery Date: 1922
SMILES Identifier: [Hf]  
InChI Identifier: InChI=1S/Hf Other Names: Afnio, Háfnio, Hafnio
InChI Key: VBJZVLUMGGDVMO-UHFFFAOYSA-N  
       
       
       
       
       

Hafnium Products

Metal Forms  •  Compounds  •  Alloys  •  Oxide Forms  •  Organometallic Compounds
Sputtering Targets  •  Nanomaterials  •  Semiconductor Materials •  Isotopes

Organometallic Compounds

Bis(cyclopentadienyl)hafnium(IV) Dichloride
Bis(ethylcyclopentadienyl)hafnium(IV) Dichloride
Bis(indenyl)halfnium(IV) Dichloride
Bis(isopropylcyclopentadienyl)hafnium(IV) Dichloride
Bis(methyl-?5-cyclopentadienyl)methoxymethylhafnium
Bis(methyl-n5-cyclopentadienyl)dimethylhafnium
Bis(tert-butoxy)bis(1-methoxy-2-methyl-2-propoxy)hafnium
Bis(tert-butylcyclopentadienyl)dimethylhafnium(IV)
Bis(tert-butylcyclopentadienyl)hafnium(IV) Dichloride
Bis(trimethylsilyl)amidohafnium(IV) Chloride
Cyclopentadienylhafnium(IV) Trichloride
Dimethylbis(cyclopentadienyl)hafnium(IV)
Hafnium 1,1,1-trifluoro-2,4-pentanedionate
Hafnium 2-Ethylhexanoate
Hafnium Acetylacetonate
Hafnium(IV) Chloride Tetrahydrofuran Complex
Hafnium Dimethylamide
Hafnium Ethoxide
Hafnium(IV) n-butoxide
Hafnium Isopropoxide Isopropanol Adduct
Hafnium(IV) tert-butoxide
Indenylhafnium(IV) Trichloride
Hafnium Trifluoromethanesulfonate
Pentamethylcyclopentadienylhafnium(IV) Trichloride
Tetrakis(1-methoxy-2-methyl-2-propoxy)hafnium(IV)
Tetrakis(diethylamido)hafnium(IV)
Tetrakis(dimethylamino)hafnium
Tetrakis(dimethylamino)hafnium(IV)
Tetrakis(ethylmethylamido)hafnium(IV)
Tetrakis(tert-butoxy)hafnium


Crystal/ Semiconductor Materials

Hafnium Oxide:Neodymium Oxide
Hafnium Oxide:Scandium Oxide
Hafnium Phosphide
Hafnium Selenide
Hafnium Silicide
Hafnium Sulfide
Hafnium Telluride


Nanomaterials

Hafnium Nanoprisms
Hafnium Nanorods
Hafnium Oxide Nanopowder


Oxide Forms

Hafnium Oxide Nanopowder
Hafnium Oxide Particles
Hafnium Oxide Pellets
Hafnium Oxide Pieces
Hafnium Oxide Powder
Hafnium Oxide Rotatable Sputtering Target
Hafnium Oxide Shot
Hafnium Oxide Sputtering Target
Hafnium Oxide Tablets


Recent Research & Development for Hafnium

  • Aaron P. Stebner, Glen S. Bigelow, Jin Yang, Dhwanil P. Shukla, Sayed M. Saghaian, Richard Rogers, Anita Garg, Haluk E. Karaca, Yuriy Chumlyakov, Kaushik Bhattacharya, Ronald D. Noebe, Transformation strains and temperatures of a nickel–titanium–hafnium high temperature shape memory alloy, Acta Materialia, Volume 76, 1 September 2014
  • Martynas Audronis, Allan Matthews, Kestutis Juškevicius, Ramutis Drazdys, Unlocking the potential of voltage control for high rate zirconium and hafnium oxide deposition by reactive magnetron sputtering, Vacuum, Volume 107, September 2014
  • Pavel G. Agraval, Liya A. Dreval, Mikhail A. Turchanin, Enthalpy of mixing of hafnium in liquid iron by high-temperature calorimetry, Journal of Alloys and Compounds, Volume 604, 15 August 2014
  • N. Manikanthababu, T.K. Chan, A.P. Pathak, G. Devaraju, N. Srinivasa Rao, P. Yang, M.B.H. Breese, T. Osipowicz, S.V.S. Nageswara Rao, Ion beam studies of Hafnium based alternate high-k dielectric films deposited on silicon, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 332, 1 August 2014
  • Jungkyu Lee, Kyriaki Polychronopoulou, Andrew N. Cloud, John R. Abelson, Andreas A. Polycarpou, Shear strength measurements of hafnium diboride thin solid films, Wear, Available online 2 July 2014
  • B.D. Briggs, S.M. Bishop, K.D. Leedy, N.C. Cady, Characterization of hafnium oxide resistive memory layers deposited on copper by atomic layer deposition, Thin Solid Films, Volume 562, 1 July 2014
  • J. Rituerto Sin, S. Suñer, A. Neville, N. Emami, Fretting corrosion of hafnium in simulated body fluids, Tribology International, Volume 75, July 2014
  • Song Tian, Hejun Li, Yulei Zhang, Jincui Ren, Xinfa Qiang, Shouyang Zhang, Hafnium carbide nanocrystal chains for field emitters, Applied Surface Science, Volume 305, 30 June 2014
  • Shuai CHEN, Zhengtang LIU, Liping FENG, Xingsen CHE, Xiaoru ZHAO, Effect of ytterbium inclusion in hafnium oxide on the structural and electrical properties of the high-k gate dielectric, Journal of Rare Earths, Volume 32, Issue 6, June 2014
  • M. Kopani, M. Mikula, E. Pincík, H. Kobayashi, M. Takahashi, FT IR spectroscopy of nitric acid oxidation of silicon with hafnium oxide very thin layer, Applied Surface Science, Volume 301, 15 May 2014
  • Magdalena Szymanska, Sylwia Gieraltowska, Lukasz Wachnicki, Marcin Grobelny, Katarzyna Makowska, Robert Mroczynski, Effect of reactive magnetron sputtering parameters on structural and electrical properties of hafnium oxide thin films, Applied Surface Science, Volume 301, 15 May 2014
  • Carmen Carney, Anish Paul, Saranya Venugopal, Triplicane Parthasarathy, Jon Binner, Allan Katz, Peter Brown, Qualitative analysis of hafnium diboride based ultra high temperature ceramics under oxyacetylene torch testing at temperatures above 2100 °C, Journal of the European Ceramic Society, Volume 34, Issue 5, May 2014
  • C. Verdon, O. Szwedek, A. Allemand, S. Jacques, Y. Le Petitcorps, P. David, High temperature oxidation of two- and three-dimensional hafnium carbide and silicon carbide coatings, Journal of the European Ceramic Society, Volume 34, Issue 4, April 2014
  • Y.D. Kolekar, L. Sanchez, E.J. Rubio, C.V. Ramana, Grain and grain boundary effects on the frequency and temperature dependent dielectric properties of cobalt ferrite–hafnium composites, Solid State Communications, Volume 184, April 2014
  • David W. Lipke, Sergey V. Ushakov, Alexandra Navrotsky, Wesley P. Hoffman, Ultra-high temperature oxidation of a hafnium carbide-based solid solution ceramic composite, Corrosion Science, Volume 80, March 2014
  • Patrice Berthod, Elodie Conrath, As-cast microstructures and behavior at high temperature of chromium-rich cobalt-based alloys containing hafnium carbides, Materials Chemistry and Physics, Volume 143, Issue 3, 14 February 2014
  • Soumitra Roy, Aloke Paul, Growth of hafnium and zirconium silicides by reactive diffusion, Materials Chemistry and Physics, Volume 143, Issue 3, 14 February 2014
  • Tao Lin, Haoqing Zhang, Hang Sun, Chen Yang, Nan Lin, Impurity free vacancy diffusion induced quantum well intermixing based on hafnium dioxide films, Materials Science in Semiconductor Processing, Available online 8 February 2014
  • Indrek Tallo, Thomas Thomberg, Heisi Kurig, Kyösti Kontturi, Alar Jänes, Enn Lust, Novel micromesoporous carbon materials synthesized from tantalum hafnium carbide and tungsten titanium carbide, Carbon, Volume 67, February 2014
  • Wesley D. Clark, Joon Cho, Henry U. Valle, T. Keith Hollis, Edward J. Valente, Metal and halogen dependence of the rate effect in hydroamination/cyclization of unactivated aminoalkenes: Synthesis, characterization, and catalytic rates of CCC-NHC hafnium and zirconium pincer complexes, Journal of Organometallic Chemistry, Volume 751, 1 February 2014

Hafnium Isotopes


Naturally occurring hafnium (Hf) has five stable isotopes: 176Hf, 177Hf, 178Hf, 179Hf, and 180Hf.

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
176Hf 175.9414086 Observationally Stable 0+
177Hf 176.9432207 Observationally Stable 7/2-
178Hf 177.9436988 Observationally Stable 0+
179Hf 178.9458161 Observationally Stable 9/2+
180Hf 179.9465500 Observationally Stable 0+