Hafnium, 72Hf
Hafnium
Pronunciation/ˈhæfniəm/ (HAF-nee-əm)
Appearancesteel gray
Standard atomic weight Ar°(Hf)
Hafnium in the periodic table
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
Atomic number (Z)72
Groupgroup 4
Periodperiod 6
Block  d-block
Electron configuration[Xe] 4f14 5d2 6s2
Electrons per shell2, 8, 18, 32, 10, 2
Physical properties
Phase at STPsolid
Melting point2506 K ​(2233 °C, ​4051 °F)
Boiling point4876 K ​(4603 °C, ​8317 °F)
Density (at 20° C)13.281 g/cm3[3]
when liquid (at m.p.)12 g/cm3
Heat of fusion27.2 kJ/mol
Heat of vaporization648 kJ/mol
Molar heat capacity25.73 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2689 2954 3277 3679 4194 4876
Atomic properties
Oxidation statescommon: +4
−2,? 0,? +1,? +2,[4], +3[4]
ElectronegativityPauling scale: 1.3
Ionization energies
  • 1st: 658.5 kJ/mol
  • 2nd: 1440 kJ/mol
  • 3rd: 2250 kJ/mol
Atomic radiusempirical: 159 pm
Covalent radius175±10 pm
Color lines in a spectral range
Spectral lines of hafnium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp) (hP2)
Lattice constants
Hexagonal close packed crystal structure for hafnium
a = 319.42 pm
c = 505.12 pm (at 20 °C)[3]
Thermal expansion5.9 µm/(m⋅K) (at 25 °C)
Thermal conductivity23.0 W/(m⋅K)
Electrical resistivity331 nΩ⋅m (at 20 °C)
Magnetic orderingparamagnetic[5]
Molar magnetic susceptibility+75.0×10−6 cm3/mol (at 298 K)[6]
Young's modulus78 GPa
Shear modulus30 GPa
Bulk modulus110 GPa
Speed of sound thin rod3010 m/s (at 20 °C)
Poisson ratio0.37
Mohs hardness5.5
Vickers hardness1520–2060 MPa
Brinell hardness1450–2100 MPa
CAS Number7440-58-6
History
Namingafter Hafnia. Latin for: Copenhagen, where it was discovered
PredictionDmitri Mendeleev (1869)
Discovery and first isolationDirk Coster and George de Hevesy (1922)
Isotopes of hafnium
Main isotopes[7] Decay
abun­dance half-life (t1/2) mode pro­duct
172Hf synth 1.87 y ε 172Lu
174Hf 0.16% 7.0×1016 y[8] α 170Yb
176Hf 5.26% stable
177Hf 18.6% stable
178Hf 27.3% stable
178m2Hf synth 31 y IT 178Hf
179Hf 13.6% stable
180Hf 35.1% stable
182Hf synth 8.9×106 y β 182Ta
 Category: Hafnium
| references
Hf · Hafnium
Lu ←

ibox Lu

iso
72
Hf  [e]
IB-Hf [e]
IBisos [e]
→ Ta

ibox Ta

indexes by PT (page)
child table, as reused in {IB-Hf}
Main isotopes of hafnium
Main isotopes[7] Decay
abun­dance half-life (t1/2) mode pro­duct
172Hf synth 1.87 y ε 172Lu
174Hf 0.16% 7.0×1016 y[8] α 170Yb
176Hf 5.26% stable
177Hf 18.6% stable
178Hf 27.3% stable
178m2Hf synth 31 y IT 178Hf
179Hf 13.6% stable
180Hf 35.1% stable
182Hf synth 8.9×106 y β 182Ta
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (46) · (this table: )

References

  1. ^ "Standard Atomic Weights: Hafnium". CIAAW. 2019.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ a b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  4. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
  5. ^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  6. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  7. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  8. ^ a b Caracciolo, V.; Nagorny, S.; Belli, P.; et al. (2020). "Search for α decay of naturally occurring Hf-nuclides using a Cs2HfCl6 scintillator". Nuclear Physics A. 1002 (121941): 121941. arXiv:2005.01373. Bibcode:2020NuPhA100221941C. doi:10.1016/j.nuclphysa.2020.121941. S2CID 218487451.