Hafnium

Hafnium, ₇₂Hf

Hafnium
Pípè	/ˈhæfniəm/ ​(HAF-nee-əm)
Ìhànsójú	steel grey
Ìwúwo átọ̀mù Ar, std(Hf)	178.486(6)
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 lutetium ← hafnium → tantalum
Nọ́mbà átọ̀mù (Z)	72
Ẹgbẹ́	group 4
Àyè	àyè 6
Àdìpọ̀	Àdìpọ̀-d
Ẹ̀ka ẹ́límẹ́ntì	Transition metal
Ìtò ẹ̀lẹ́ktrọ́nù	[Xe] 4f14 5d2 6s2
Iye ẹ̀lẹ́ktrọ́nù lórí ìpele kọ̀ọ̀kan	2, 8, 18, 32, 10, 2
Àwọn ohun ìní ara
Ìfarahàn at STP	solid
Ìgbà ìyọ́	2506 K ​(2233 °C, ​4051 °F)
Ígbà ìhó	4876 K ​(4603 °C, ​8317 °F)
Kíki (near r.t.)	13.31 g/cm3
when liquid (at m.p.)	12 g/cm3
Heat of fusion	27.2 kJ/mol
Heat of	571 kJ/mol
Molar heat capacity	25.73 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
Electronegativity	Pauling scale: 1.3
Atomic radius	empirical: 159 pm
Covalent radius	175±10 pm
Spectral lines of hafnium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal
Speed of sound thin rod	3010 m/s (at 20 °C)
Thermal expansion	5.9 µm/(m·K) (at 25 °C)
Thermal conductivity	23.0 W/(m·K)
Electrical resistivity	331 n Ω·m (at 20 °C)
Magnetic ordering	paramagnetic
Young's modulus	78 GPa
Shear modulus	30 GPa
Bulk modulus	110 GPa
Poisson ratio	0.37
Mohs hardness	5.5
Vickers hardness	1760 MPa
Brinell hardness	1700 MPa
CAS Number	7440-58-6
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