72 lutetium ← hafnium → tantalum Zr ↑ Hf ↓ Rf Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	hafnium, Hf, 72
Chemical series	transition metals
Group, Period, Block	4, 6, d
Appearance	steel grey
Standard atomic weight	178.49(2)  g·mol−1
Electron configuration	[Xe] 4f14 5d2 6s2
Electrons per shell	2, 8, 18, 32, 10, 2
Physical properties
Phase	solid
Density (near r.t.)	13. Lutetium (ljuːˈtiːʃiəm is a Chemical element with the symbol Lu and Atomic number 71 Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Rutherfordium (ˌrʌðɚˈfɔrdiəm is a Chemical element in the Periodic table that has the symbol Rf and Atomic number 104 This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A block of the Periodic table of elements is a set of adjacent groups The respective highest-energy electrons in each element in a block belong to the same Atomic Biological occurances The group 4 elements are not known to be involved in the biological chemistry of any living systems A period 6 element is one of the Chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides The d-block of the periodic table of the elements consists of those Periodic table groups that contain elements in which in the atomic ground state the highest-energy The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed 31  g·cm−3
Liquid density at m.p.	12  g·cm−3
Melting point	2506 K (2233 °C, 4051 °F)
Boiling point	4876 K (4603 °C, 8317 °F)
Heat of fusion	27. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 2  kJ·mol−1
Heat of vaporization	571  kJ·mol−1
Specific heat capacity	(25 °C) 25. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 73  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 2689 2954 3277 3679 4194 4876
Atomic properties
Crystal structure	hexagonal
Oxidation states	4 (amphoteric oxide)
Electronegativity	1. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 3 (Pauling scale)
Ionization energies (more)	1st:  658. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron These tables list the Ionization energy in kJ/mol necessary to remove one mole of Electrons from one mole of neutral gaseous Atoms (first energy respectively 5  kJ·mol−1
	2nd:  1440  kJ·mol−1
	3rd:  2250  kJ·mol−1
Atomic radius	155  pm
Atomic radius (calc. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth )	208  pm
Covalent radius	150  pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(20 °C) 331 n Ω·m
Thermal conductivity	(300 K) 23. The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of Electric current. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. 0  W·m−1·K−1
Thermal expansion	(25 °C) 5. When the Temperature of a substance changes the energy that is stored in the Intermolecular bonds between atoms changes 9  µm·m−1·K−1
Speed of sound (thin rod)	(20 °C) 3010 m/s
Young's modulus	78  GPa
Shear modulus	30  GPa
Bulk modulus	110  GPa
Poisson ratio	0. Sound is a vibration that travels through an elastic medium as a Wave. In Solid mechanics, Young's modulus (E is a measure of the Stiffness of an isotropic elastic material In Materials science, shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is defined as the ratio of Shear Poisson's ratio ( ν) named after Simeon Poisson, is the ratio of the relative contraction strain, or transverse strain (normal to 37
Mohs hardness	5. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 5
Vickers hardness	1760  MPa
Brinell hardness	1700  MPa
CAS registry number	7440-58-6
Selected isotopes
Main article: Isotopes of hafnium iso NA half-life DM DE (MeV) DP 172Hf syn 1. The Vickers hardness test was developed in 1924 by Smith and Sandland as an alternative method to measure the Hardness of materials The Brinell scale characterizes the indentation Hardness of materials through the scale of penetration of an indenter loaded on a material test-piece CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Hafnium ( Hf)Standard atomic mass 17849(2 u Table Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a Nuclide A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 87 y ε 0. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the 350 172Lu 174Hf 0. Lutetium (ljuːˈtiːʃiəm is a Chemical element with the symbol Lu and Atomic number 71 162% 2×1015 y α 2. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle 495 170Yb 176Hf 5. 206% 176Hf is stable with 104 neutrons 177Hf 18. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 606% 177Hf is stable with 105 neutrons 178Hf 27. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 297% 178Hf is stable with 106 neutrons 178m2Hf syn 31 y IT 2. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions 446 178Hf 179Hf 13. 629% 179Hf is stable with 107 neutrons 180Hf 35. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 1% 180Hf is stable with 108 neutrons 182Hf syn 9×106 y β 0. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 373 182Ta
References

Hafnium (pronounced /ˈhæfniəm/) is a chemical element that has the symbol Hf and atomic number 72. Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 Recommended values for many properties of the elements together with various references are collected on these data pages A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. See also Chemical formula. A chemical symbol is an Abbreviation or shortened version of the name of a Chemical element See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton A lustrous, silvery gray tetravalent transition metal, hafnium resembles zirconium chemically and it is found in zirconium minerals. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. In Chemistry, a tetravalence is the state of an Atom with four Electrons available for covalent chemical bonding in its valence In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Hafnium is used in tungsten alloys in filaments and electrodes, in integrated circuits as a gate insulator for transistors, and as a neutron absorber in control rods in nuclear power plants. Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 An alloy is a Solid solution or Homogeneous mixture of two or more elements, at least one of which is a Metal, which itself has An electrical filament is a thread of Metal, usually Tungsten, which is used to convert Electricity into light in Incandescent light bulbs (as developed An electrode is an Electrical conductor used to make contact with a nonmetallic part of a circuit (e Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside The metal–oxide–semiconductor field-effect transistor ( MOSFET, MOS-FET, or MOS FET) is a device used to amplify or switch electronic signals This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A control rod is a rod made of Chemical elements capable of absorbing many Neutrons without fissioning themselves Nuclear power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions

Notable characteristics

Hafnium metal

Hafnium is a shiny silvery, ductile metal that is corrosion resistant and chemically similar to zirconium. Ductility is a mechanical property used to describe the extent to which materials can be deformed plastically or "stretched" into "wires" without The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Corrosion means the breaking down of essential properties in a material due to Chemical reactions with its surroundings Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 The physical properties of hafnium are markedly affected by zirconium impurities, and these two elements are among the most difficult ones to separate. A notable physical difference between them is their density (zirconium being about half as dense as hafnium), but chemically the elements are extremely similar.

The most notable physical property of hafnium is that it has a very high neutron-capture cross-section, and nuclei of several hafnium isotopes can each absorb multiple neutrons. This makes hafnium a good material for use in the control rods for nuclear reactors. A control rod is a rod made of Chemical elements capable of absorbing many Neutrons without fissioning themselves This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled Its neutron-capture cross-section is about 600 times that of zirconium's. (Other elements that are good neutron-absorbers for control rods are cadmium and boron. Cadmium (ˈkædmiəm is a Chemical element with the symbol Cd and Atomic number 48 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. )

Separation of hafnium and zirconium becomes very important in the nuclear power industry, since zirconium is a good fuel-rod cladding metal, with the desirable properties of a very low neutron capture cross-section and good chemical stability at high temperatures. However, because of hafnium's neutron-absorbing properties, hafnium impurities in zirconium would cause it to be far less useful for nuclear reactor applications. Thus a nearly complete separation of zirconium and hafnium is necessary for their use in nuclear power.

Hafnium carbide is the most refractory binary compound known, with a melting point over 3890 °C, and hafnium nitride is the most refractory of all known metal nitrides, with a melting point of 3310 °C. Hafnium carbide ( Hf[[Carbon C]] is a Chemical compound. It is the most refractory Binary compound known with a melting point over In Metallurgy, refraction is a property of Metals that indicates their ability to withstand Heat. A binary compound is a compound that contains two different elements such as NaCl (salt or Sodium chloride) The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The Celsius Temperature scale was previously known as the centigrade scale. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The Celsius Temperature scale was previously known as the centigrade scale. ^[1] This has led to proposals that hafnium or its carbides might be useful as construction materials that are subjected to very high temperatures.

The metal is resistant to concentrated alkalis, but halogens react with it to form hafnium tetrahalides. In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions ^[1] At higher temperatures hafnium reacts with oxygen, nitrogen, carbon, boron, sulfur, and silicon. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14

The nuclear isomer Hf-178-m2 is also a source of cascades of gamma rays whose energies total 2. A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions 45 MeV per decay. ^[2] It is notable because it has the highest excitation energy of any comparably long-lived isomer of any element. One gram of pure Hf-178-m2 would contain approximately 1330 megajoules of energy, the equivalent of exploding about 317 kilograms (700 pounds) of TNT. Trinitrotoluene ( TNT) is a Chemical compound with the formula C6H2(NO23CH3 Possible applications requiring such highly concentrated energy storage are of interest. For example, it has been studied as a possible power source for gamma ray lasers. A laser is a device that emits Light ( Electromagnetic radiation) through a process called Stimulated emission. ^[3]

Applications

Hafnium is used to make control rods for nuclear reactors because of its ability to absorb neutrons (its thermal neutron absorption cross section is nearly 600 times that of zirconium), excellent mechanical properties and exceptional corrosion-resistance properties. This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron.

Other uses:

• In gas-filled and incandescent lamps, for scavenging oxygen and nitrogen,
• As the electrode in plasma cutting because of its ability to shed electrons into air,
• In iron, titanium, niobium, tantalum, and other metal alloys. The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general This article is about the common Manufacturing process For various fictional weapons see Plasma rifle and Directed-energy weapon. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 Niobium (naɪˈoʊbiəm or columbium (/kəˈlʌmbiəm/ is a Chemical element that has the symbol Nb and Atomic number 41 Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 An alloy is a Solid solution or Homogeneous mixture of two or more elements, at least one of which is a Metal, which itself has
• A hafnium-based compound is employed in gate insulators in the 45 nm generation of integrated circuits from Intel, IBM and others ^[4]. The field-effect transistor (FET is a type of Transistor that relies on an Electric field to control the shape and hence the conductivity of a 'channel' Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology Hafnium oxide-based compounds are practical high-k dielectrics, allowing reduction of the gate leakage current which improves performance at such scales. The term high-κ Dielectric refers to a material with a high Dielectric constant (κ (as compared to Silicon dioxide) used in semiconductor manufacturing ^[5][6]
• DARPA has been intermittently funding programs in the US to determine the possibility of using a nuclear isomer of hafnium (the above mentioned Hf-178-m2) to construct small, high yield weapons with simple x-ray triggering mechanisms—an application of induced gamma emission. The Defense Advanced Research Projects Agency (DARPA is an agency of the United States Department of Defense responsible for the development of new Technology A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies In Physics, induced gamma emission ( IGE) refers to the process of fluorescent emission of Gamma rays from excited nuclei usually involving a specific That work follows over two decades of basic research by an international community^[7] into the means for releasing the stored energy upon demand. There is considerable opposition to this program, both because the idea may not work^[8], and because uninvolved countries might perceive an imagined "isomer weapon gap" that would justify their further development and stockpiling of conventional nuclear weapons. A related proposal is to use the same isomer to power Unmanned Aerial Vehicles,^[9] which could remain airborne for months at a time. An unmanned aerial vehicle (UAV is an unpiloted Aircraft. UAVs can be remote controlled or fly autonomously based on pre-programmed flight plans or more complex dynamic
• Small additions of hafnium increase the adherence of protective oxide scales on nickel based alloys. It improves thereby the corrosion resistance especially under cyclic temperature conditions that tend to break oxide scales by inducing thermal stresses between the bulk material and the oxide layer.

History

The hafnium seal of the Faculty of Science of the University of Copenhagen

The 1869 periodic table by Mendeleev had implicitly predicted the existence of a heavier analog of titanium and zirconium, but in 1871 Mendeleev placed lanthanum (element 57) in that spot. The Faculty of Science ( Det naturvidenskabelige fakultet in Danish at the University of Copenhagen consists of both mathematical and natural sciences and is divided Dmitri Ivanovich Mendeleev (sometimes spelled Mendeleyev; Дми́трий Ива́нович Менделе́ев) ( &ndash) was a Russian chemist and Professor Dmitri Mendeleev published the first Periodic Table of the Atomic Elements in 1869 based on properties which appeared with some regularity as he laid out the elements Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Lanthanum (ˈlænθənəm is a Chemical element with the symbol La and Atomic number 57

The existence of a gap in the periodic table for a yet to be discovered element 72 was predicted by Henry Moseley in 1914. Henry Gwyn Jeffreys Moseley ( November 23, 1887 – August 10, 1915) was an English physicist. Hafnium was named for the Latin name Hafnia for "Copenhagen", the home town of Niels Bohr. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Copenhagen (ˌkəʊpənˈheɪgən ˌkəʊpənˈhɑːgən ˈkəʊpənˌheɪgən ˈkəʊpənˌhɑːgən kʰøb̥ənˈhɑʊ̯ˀn kʰøb̥m̩ˈhɑʊ̯ˀn is the capital and largest city Niels Henrik David Bohr (nels ˈb̥oɐ̯ˀ in Danish 7 October 1885 – 18 November 1962 was a Danish Physicist who made fundamental contributions to understanding It was discovered by Dirk Coster and Georg von Hevesy in 1923 in Copenhagen, Denmark, validating the original 1869 prediction of Mendeleev. Dirk Coster ( October 5, 1889 &ndash February 12, 1950) was a Dutch Physicist. Georg Karl von Hevesy ( August 1, 1885 &ndash July 5, 1966) was a Hungarian radiochemist and Nobel laureate recognised Year 1923 ( MCMXXIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar. The Kingdom of Denmark ( ˈd̥ænmɑɡ̊ (archaic ˈd̥anmɑːɡ̊ commonly known as Denmark, is a country in the Scandinavian region of northern Europe Soon thereafter, the new element was predicted to be associated with zirconium by using the Bohr theories of the atom, and it was finally found in zircon through X-ray spectroscopy analysis in Norway. Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Zircon is a Mineral belonging to the group of nesosilicates. Its chemical name is Zirconium silicate and its corresponding chemical formula is X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional

Hafnium was separated from zirconium through repeated recrystallization of the double ammonium or potassium fluorides by Jantzen and von Hevesey. Ammonium is also an old name for the Siwa Oasis in western Egypt. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Metallic hafnium was first prepared by Anton Eduard van Arkel and Jan Hendrik de Boer by passing hafnium tetra-iodide vapor over a heated tungsten filament. Anton Eduard van Arkel, ( 's-Gravenzande Netherlands, November 19, 1893 &ndash Leiden, March 14 1976) was a Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 This process for differential purification of Zr and Hf is still in use today.

The Faculty of Science of the University of Copenhagen uses in its seal a stylized image of hafnium. The Faculty of Science ( Det naturvidenskabelige fakultet in Danish at the University of Copenhagen consists of both mathematical and natural sciences and is divided The University of Copenhagen (Københavns Universitet is the oldest and largest University and research institution in Denmark. A seal can mean a wax seal bearing an impressed figure or an embossed figure in paper with the purpose of authenticating a document but the term can also mean any device for

Occurrence

Hafnium is estimated to make up about 0. 00058% of the Earth's upper crust by weight. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 In Geology, a crust is the outermost solid shell of a planet or moon It is found combined in natural zirconium compounds but it does not exist as a free element in nature. Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Minerals that contain zirconium, such as alvite [(Hf, Th, Zr)SiO₄ H₂O], thortveitite, and zircon (ZrSiO₄), usually contain between 1 and 5% hafnium. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Thorium (ˈθɔːriəm is a Chemical element with the symbol Th and Atomic number 90 Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Water is a common Chemical substance that is essential for the survival of all known forms of Life. Thortveitite is a Mineral consisting of Scandium Yttrium Silicate (ScY2Si2O7 Zircon is a Mineral belonging to the group of nesosilicates. Its chemical name is Zirconium silicate and its corresponding chemical formula is Hafnium and zirconium have nearly identical chemistry, which makes the two difficult to separate. About half of all hafnium metal manufactured is produced as a by-product of zirconium refinement. This is done through reducing hafnium(IV) chloride with magnesium or sodium in the Kroll process. Hafnium(IV chloride is the Inorganic compound with the formula HfCl4 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 The Kroll process is a Pyrometallurgical industrial process used to produce metallic Titanium.

A lump of hafnium which has been oxidized on one side and exhibits thin film optical effects. Thin-film optics is the branch of Optics that deals with very thin structured layers of different materials

A major source of zircon (and hence hafnium) ores are heavy mineral sands ore deposits, pegmatites particularly in Brazil and Malawi, and carbonatite intrusions particularly the Crown Polymetallic Deposit at Mount Weld, Western Australia. Heavy mineral Sands are a class of Ore deposit which is an important source of Zirconium, Titanium, Thorium, Tungsten, Pegmatite is a very coarse-grained Igneous rock that has a grain size of 20 mm or more such rocks are referred to as pegmatitic. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld The Republic of Malawi (məˈlɑːwi or; formerly Nyasaland) is in southern Africa. Carbonatites (kɑrˈbɒnətaɪt are Intrusive or extrusive Igneous rocks defined by mineralogy that comprises more than 50 volume-% Carbonate A potential source of hafnium is trachyte tuffs containing rare zircon-hafnium silicates eudialyte or armostrongite, at Dubbo in New South Wales, Australia. Eudialyte, whose name derives from the Greek eu and dialytos, meaning "well decomposable" is a somewhat rare red Silicate Dubbo is a city in the Central West Region of New South Wales, Australia. ^[10]

One chemist estimated in 2007 that at the current rate of usage, the worlds supply of hafnium would be exhausted by about the year 2017. ^[11]

Precautions

Care needs to be taken when machining hafnium because, like its sister metal zirconium, when hafnium is divided into fine particles, it is pyrophoric and can ignite spontaneously in air (see Dragon's Breath for a demonstration). A pyrophoric substance will ignite spontaneously that is its Autoignition temperature is below Room temperature. A Dragon's Breath usually refers to a Zirconium -based pyrotechnic Shotgun round Compounds that contain this metal are rarely encountered by most people. The pure metal is not considered toxic, but hafnium compounds should be handled as if they are toxic because the ionic forms of metals are normally at greatest risk for toxicity, and limited animal testing has been done for hafnium compounds.

Isotopes

Main article: Isotopes of hafnium

Hafnium has five stable isotopes. Hafnium ( Hf)Standard atomic mass 17849(2 u Table

Compounds

See also: Category:Hafnium compounds

See also

• Nuclear isomer
• Induced gamma emission
• Zircon

References

1. ^ ^{a b} Los Alamos National Laboratory – Hafnium
2. ^ WWW Table of Radioactive Isotopes, Lawrence Berkeley National Laboratory Isotopes Project and Lund University. A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies In Physics, induced gamma emission ( IGE) refers to the process of fluorescent emission of Gamma rays from excited nuclei usually involving a specific Zircon is a Mineral belonging to the group of nesosilicates. Its chemical name is Zirconium silicate and its corresponding chemical formula is
3. ^ C. B. Collins et al. (2004). "Nuclear resonance spectroscopy of the 31-yr isomer of Hf-178". Laser Physics Letters 2 (3): 162–167. doi:10.1002/lapl.200410154. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
4. ^ Markoff, John. "Intel Says Chips Will Run Faster, Using Less Power", New York Times, January 27, 2007. Events 98 - Trajan becomes Roman Emperor after the death of Nerva. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Retrieved on 2007-09-19. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 335 - Dalmatius is raised to the rank of Caesar by his uncle Constantine I.  
5. ^ Fulton, III, Scott M. . "Intel Reinvents the Transistor", BetaNews, January 27, 2007. Events 98 - Trajan becomes Roman Emperor after the death of Nerva. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Retrieved on 2007-01-27. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 98 - Trajan becomes Roman Emperor after the death of Nerva.  
6. ^ Robertson, Jordan. "Intel, IBM reveal transistor overhaul", AP, January 27, 2007. Events 98 - Trajan becomes Roman Emperor after the death of Nerva. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Retrieved on 2007-09-19. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 335 - Dalmatius is raised to the rank of Caesar by his uncle Constantine I.  
7. ^ Induced gamma emission history, The Center for Quantum Electronics, The University of Texas at Dallas.
8. ^ Schwarzschild, Bertram (May 2004). Conflicting Results on a Long-Lived Nuclear Isomer of Hafnium Have Wider Implications. Physics Today. Retrieved on 2007-09-19. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 335 - Dalmatius is raised to the rank of Caesar by his uncle Constantine I.
9. ^ Nuclear-powered drone aircraft on drawing board. New Scientist. Retrieved on 2008-06-06. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1508 - Maximilian I Holy Roman Emperor, is defeated in Friulia by Venetian forces; he is forced to sign a three-year
10. ^ Dubbo Zirconia Project Fact Sheet (PDF). Alkane Resources Limited (June 2007). Retrieved on 2007-09-10. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 506 - The Bishops of Visigothic Gaul meet in the Council of Agde.
11. ^ Augsberg University Calculate When Our Materials Run Out retrieved May 4, 2008

• van Arkel, A. E. , and de Boer, J. H. (1925). "Preparation of pure titanium, zirconium, hafnium, and thorium metal". Zeitschrift für Anorganische und Allgemeine Chemie 148: 345–350.  

Scerri, E. R. , Prediction of the Nature of Hafnium from Chemistry, Bohr’s Theory and Quantum Theory, Annals of Science, 51, 137-150, (1994)

External links

• WebElements.com – Hafnium
• Hafnium Technical & Safety Data
• NLM Hazardous Substances Databank – Hafnium, elemental
• Intel Shifts from Silicon to Lift Chip Performance
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