Hafnium, including Technical Data, Safety Data and its high purity 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 oxidesemiconductor 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 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 nanopowdersprovide 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 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. 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. Hafnium is not toxic. 

All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, thin fillm deposition using sputtering targets technology applications. Information is provided for stable (non-radioactive) isotopes. Organo-Metallic Hafnium compounds are soluble in organic or non-aqueous solvents. SeeAnalytical 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.

Abundance. The following table shows the abundance of hafnium and each of its naturally occurringisotopes 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 The following table shows the abundance of Hafnium present in the human body and in the universe scaled to parts per billion (ppb) by weight and by atom:   Typical Human Body Universe by Weight no data 0.7 ppb by Atom no data 0.005 ppb Safety Data and Biological Role. 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. Hafniumcompounds have no biological role.  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 ?C 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