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Hafnium information, including Technical Data, Safety Data and its properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.

Hafnium is one of the Group IV transition elements that is refined from various zirconic mineral deposits. Hafnium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity); metals in the form of foil, sputtering target, and rod, and compounds as submicron and nanopowder. It's primary uses are due to its ability as a nuclear "getter" or absorber of neutrons. It is a primary component in nuclear control rods for this purpose. It also finds uses as a dopant in the alloy of steel and titanium. It is also used in the production of mantles for high intensity incandescent lamps.

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 have gotten 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.

Hafnium facts, including appearance, CAS #, and molecular formula and safety data, research and properties are

 

  Hydrogen                                 Helium
  Lithium Beryllium                     Boron Carbon Nitrogen Oxygen Fluorine Neon
  Sodium Magnesium                     Aluminum 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
  Cesium Barium Cerium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon
                                     
      Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium    
      Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium    


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available for many specific states, forms and shapes on the product pages listed to the left. Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. 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 forms including powders and dense pellets 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 available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries.

Hafnium is a Block D, Group 4, Period 6 element. The electronic configuration is [Xe] 4f14 5d2 6s2. In its elemental form hafnium's CAS number is 7440-58-6. The hafnium atom has a radius of 156.4.pm and it's Van der Waals radius is 200.pm.

All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, metallurgy and optical materials and other high technology advantages. Information is provided for stable (non-radioactive) isotopes. Organo-Metallic Hafnium compounds are soluble in organic or non-aqueous solvents. See Analytical Services for information on available certified chemical and physical analysis techniques including MS-ICP, X-Ray Diffraction, PSD and Surface Area (BET) analysis.

Hafnium was first discovered by Dirk Coster in 1923.

French hafnium German Hafnium Italian afnio Portuguese Háfnio Spanish hafnio Swedish Hafnium

Abundance. The following table shows the abundance of hafnium and each of its naturally occurring isotopes on Earth along with the atomic mass for each isotope.

Isotope
Atomic Mass
% Abundance on Earth
Hf-174
173.940040
0.162
Hf-176
175.941402
5.206
Hf-177
176.943220
18.606
Hf-178
177.943698
27.297
Hf-179
178.945815
13.629
Hf-180
179.946549
35.100

Safety Data. The safety data for hafnium metal, nanoparticles 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 left margin.

Ionization Energy. The ionization energy for hafnium (the least required energy to release a single electron from the atom in it's ground state in the gas phase) is stated in the following table:

1st Ionization Energy
658.52 kJ mol-1
2nd Ionization Energy
1437.64 kJ mol-1
3rd Ionization Energy
2248.12 kJ mol-1

Conductivity. As to hafnium's electrical and thermal conductivity, the electrical conductivity measured as to electrical resistivity @ 20 ºC is 33.08 μΩcm and its electronegativities (or its ability to draw electrons relative to other elements) is 1.3. The thermal conductivity of hafnium is 23 W m-1 K-1.

Thermal Properties. The melting point and boiling point for hafnium are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization.

Heat of Fusion
25.5 kJ mol-1
Heat of Vaporization
570.7 kJ mol-1
Heat of Atomization
618.9 kJ mol-1

 
Formula Atomic Number Molecular Weight Electronegativity (Pauling) Density Melting Point
Boiling Point
Vanderwaals radius
Ionic radius Energy of first ionization
Hf 72 178.49 g.mol -1 1.3 13.07 g.cm-3 at 20 °C 2200 °C 5200 °C 200.pm 0.075 nm (+4) 658.52 kJ.mol-1

PRODUCT CATALOG UK Operations Submicron & Nanopowder Tolling Ultra High Purity Sputtering Target Crystal Growth Rod, Plate, Powder, etc. Foil
 
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Recent Research & Development for Hafnium

  • Self-assembly and crystallization behavior of mesoporous, crystalline HfO2 thin films: a model system for the generation of mesostructured transition-metal oxides.
    Small. 2005 Aug;1(8-9):889-98.

  • Guanidinate-Stabilized Monomeric Hafnium Amide Complexes as Promising Precursors for MOCVD of HfO2.
    Inorg Chem. 2006 Dec 25;45(26):11008-18.

  • A stable Schrock-type hafnium-silylene complex.
    J Am Chem Soc. 2006 Dec 20;128(50):16024-5. No abstract available.

  • Dinitrogen functionalization with bis(cyclopentadienyl) complexes of zirconium and hafnium.
    Dalton Trans. 2007 Jan 7;(1):16-25. Epub 2006 Nov 23.

  • Recent progress in polar stationary phases for CEC.
    Electrophoresis. 2006 Nov 29; [Epub ahead of print]

  • Antimony-antimony bond formation by reductive elimination from a hafnium bis(stibido) complex.
    Inorg Chem. 2006 Nov 27;45(24):9625-7.

  • Analysis of FT-IR spectra of dicyclopentadienyl (bis-substituted cyclopentadienyl) dithiocyano of titanium, zirconium and hafnium.
    Spectrochim Acta A Mol Biomol Spectrosc. 2006 Sep 24; [Epub ahead of print]

  • Syntheses and X-ray crystal structures of zirconium(IV) and hafnium(IV) complexes containing monovacant wells-Dawson and Keggin polyoxotungstates.
    Inorg Chem. 2006 Oct 2;45(20):8108-19.

  • N-C bond formation promoted by a hafnocene dinitrogen complex: comparison of zirconium and hafnium congeners.
    J Am Chem Soc. 2006 Aug 23;128(33):10696-7. No abstract available.

  • Group 4 transition-metal atom reactions with CS2 and OCS: infrared spectra and density functional calculations of SMCS, SM-(eta2-CS), SMCO, and OMCS in solid argon.
    J Phys Chem A Mol Spectrosc Kinet Environ Gen Theory. 2006 Nov 30;110(47):12785-92.

 

 

 

 

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