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

  • Laser-induced damage in composites of scandium, hafnium, aluminum oxides with silicon oxide in the infrared. Fu X, Commandré M, Gallais L, Mende M, Ehlers H, Ristau D. Appl Opt. 2014
  • Hafnium-silicon precipitate structure determination in a new heat-resistant ferritic alloy by precession electron diffraction techniques. Viladot D, Portillo J, Gemí M, Nicolopoulos S, Llorca-Isern N. Microsc Microanal. 2014 Feb.
  • A novel nonanuclear hafnium oxide-hydroxide-sulphate cluster crystallised from aqueous solution. - Kalaji A, Soderholm L. Chem Commun (Camb). 2014 Jan.
  • Unusual Hafnium-Pyridylamido/ERn Heterobimetallic Adducts (ERn =ZnR2 or AlR3 ). Rocchigiani L, Busico V, Pastore A, Talarico G, Macchioni A. Angew Chem Int Ed Engl. 2014 Jan.
  • Determination of hafnium at the 10(-4)% level (relative to zirconium content) using neutron activation analysis, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. Smolik M, Polkowska-Motrenko H, Hubicki Z, Jakóbik-Kolon A, Danko B. Chim Acta. 2014 Jan
  • Corrosion and tribocorrosion of hafnium in simulated body fluids. Rituerto Sin J, Neville A, Emami N. J Biomed Mater Res B Appl Biomater. 2013 Dec 26.
  • A novel nonanuclear hafnium oxide-hydroxide-sulphate cluster crystallised from aqueous solution. Kalaji A, Soderholm L. Chem Commun (Camb). 2013.
  • Activation of dinitrogen-derived hafnium nitrides for nucleophilic n?c bond formation with a terminal isocyanate. Semproni SP, Chirik PJ. Angew Chem Int Ed Engl. 2013 Dec 2.
  • Slow DNA Transport through Nanopores in Hafnium Oxide Membranes. Larkin J, Henley R, Bell DC, Cohen-Karni T, Rosenstein JK, Wanunu M. ACS Nano. 2013.
  • Simultaneous determinations of zirconium, hafnium, yttrium and lanthanides in seawater according to a co-precipitation technique onto iron-hydroxide. Raso M, Censi P, Saiano F. Talanta. 2013 Nov
  • Aminopyridinate-FI Hybrids, Their Hafnium and Titanium Complexes, and Their Application in the Living Polymerization of 1-Hexene. Haas I, Dietel T, Press K, Kol M, Kempe R. Chemistry. 2013 Oct.
  • Activation of Dinitrogen-Derived Hafnium Nitrides for Nucleophilic N?C Bond Formation with a Terminal Isocyanate. Semproni SP, Chirik PJ. Angew Chem Int Ed Engl. 2013 Oct 9.
  • Slow DNA Transport through Nanopores in Hafnium Oxide Membranes. Larkin J, Henley R, Bell DC, Cohen-Karni T, Rosenstein JK, Wanunu M. ACS Nano. 2013.
  • Effects of trimethylaluminium and tetrakis(ethylmethylamino) hafnium in the early stages of the atomic-layer-deposition of aluminum oxide and hafnium oxide on hydroxylated GaN nanoclusters. León-Plata PA, Coan MR, Seminario JM. J Mol Model. 2013 Oct.
  • Aminopyridinate-FI Hybrids, Their Hafnium and Titanium Complexes, and Their Application in the Living Polymerization of 1-Hexene. Haas I, Dietel T, Press K, Kol M, Kempe R. Chemistry. 2013 Sep 3.
  • Effects of trimethylaluminium and tetrakis(ethylmethylamino) hafnium in the early stages of the atomic-layer-deposition of aluminum oxide and hafnium oxide on hydroxylated GaN nanoclusters. León-Plata PA, Coan MR, Seminario JM. J Mol Model. 2013.
  • Synthesis of a Base-Free Hafnium Nitride from N2 Cleavage: A Versatile Platform for Dinitrogen Functionalization. Semproni SP, Chirik PJ. J Am Chem Soc. 2013.
  • Zirconium and Hafnium Complexes Containing N-Alkyl-Substituted Amine Biphenolate Ligands: Unexpected Ligand Degradation and Divergent Complex Constitutions Governed by N-Alkyls. Liang LC, Chien CC, Chen MT, Lin ST. Inorg Chem.
  • Hafnium(IV) Tetratriflate as a Glycosyl Fluoride Activation Reagent. Manabe S, Ito Y. J Org Chem.
  • The molecular frame electric dipole moment and hyperfine interactions in hafnium fluoride, HfF. Le A, Steimle TC, Skripnikov L, Titov AV. J Chem Phys. 2013.

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+