Hafnium, 72Hf
Hafnium
Pípè /ˈhæfniəm/ (HAF-nee-əm)
Ìhànsójústeel grey
Ìwúwo átọ̀mù Ar, std(Hf)178.486(6)[1]
Hafnium ní orí tábìlì àyè
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium 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
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Zr

Hf

Rf
lutetiumhafniumtantalum
Nọ́mbà átọ̀mù (Z)72
Ẹgbẹ́group 4
Àyèàyè 6
Àdìpọ̀Àdìpọ̀-d
Ẹ̀ka ẹ́límẹ́ntì  Transition metal
Ìtò ẹ̀lẹ́ktrọ́nù[Xe] 4f14 5d2 6s2
Iye ẹ̀lẹ́ktrọ́nù lórí ìpele kọ̀ọ̀kan2, 8, 18, 32, 10, 2
Àwọn ohun ìní ara
Ìfarahàn at STPsolid
Ìgbà ìyọ́2506 K ​(2233 °C, ​4051 °F)
Ígbà ìhó4876 K ​(4603 °C, ​8317 °F)
Kíki (near r.t.)13.31 g/cm3
when liquid (at m.p.)12 g/cm3
Heat of fusion27.2 kJ/mol
Heat of 571 kJ/mol
Molar heat capacity25.73 J/(mol·K)
 pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2689 2954 3277 3679 4194 4876
Atomic properties
Oxidation states−2, +1, +2, +3, +4 Àdàkọ:Infobox element/symbol-to-oxidation-state/comment
ElectronegativityPauling scale: 1.3
Atomic radiusempirical: 159 pm
Covalent radius175±10 pm
Color lines in a spectral range
Color lines in a spectral range
Spectral lines of hafnium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal
Hexagonal crystal structure for hafnium
Speed of sound thin rod3010 m/s (at 20 °C)
Thermal expansion5.9 µm/(m·K) (at 25 °C)
Thermal conductivity23.0 W/(m·K)
Electrical resistivity331 n Ω·m (at 20 °C)
Magnetic orderingparamagnetic[2]
Young's modulus78 GPa
Shear modulus30 GPa
Bulk modulus110 GPa
Poisson ratio0.37
Mohs hardness5.5
Vickers hardness1760 MPa
Brinell hardness1700 MPa
CAS Number7440-58-6
Main isotopes of hafnium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
172Hf syn 1.87 y ε 0.350 172Lu
174Hf 0.162% 2×1015 y α 2.495 170Yb
176Hf 5.206% 176Hf is stable with 104 neutrons
177Hf 18.606% 177Hf is stable with 105 neutrons
178Hf 27.297% 178Hf is stable with 106 neutrons
178m2Hf syn 31 y IT 2.446 178Hf
179Hf 13.629% 179Hf is stable with 107 neutrons
180Hf 35.1% 180Hf is stable with 108 neutrons
182Hf syn 9×106 y β 0.373 182Ta
Àdàkọ:Category-inline
| references


  1. Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry 88 (3): 265–91. doi:10.1515/pac-2015-0305. 
  2. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.