• Class: Transition Metals
• Period: 6
• IUPAC group: 4
• Traditional: IVa

• Discovered in: 1923 by Coster, von Hevesey
• Origin of name: Hafnia, LaTin name for Copenhagen
• Historical or alternate name:

Zircon

Highly lustrous, ductile, Silvery grey metal. Exposed surfaces form oxide film. Resists alkalis and acids (except HF). Burns in air.

• Atmosphere: ~0.0 ppm
• Primitive mantle: 0.27 ppm
• Sea water: 0.008 ppm
• Metallic meteorite: 0.119 ppm
• ConTinental crust: 3.0 ppm
• Solar photosphere: 0.8 log of abundance
• Oceanic crust: 2.5 ppm
• Solar system: 0.176 relative to Si=1.0e6

   Hazards

Toxic. Metal ignites and burns readily..

• Lower:
• Upper:

Hafnium Physical Properties

 Transitional Data

• State: Solid
• Density: 13.31 g/cm3

 Molar enthalpy

• Atomization: 618.90 kJ mol-1
• Fusion: 25.5 kJ mol-1
• Vaporization: 570.7 kJ mol-1

 Transition points

• MelTing point: 2500.0 K
• Boiling point: 4875.0 K
• Critical temperature: 10400.0 K

 Molar properties

• Atomic weight: 178.49 g/mole
• Molar volume: 13.526 cm3 mol-1

 Crystal structure sequence

hexagonal-close-packed <2268 K < body-centered-cubic < melTing point

 Thermodynamics

• State: solid
  • Enthalpy 0
  • Gibbs function 0
  • Entropy 43.56
  • Heat Capacity 25.73

• State: gas
  • Enthalpy 619.2
  • Gibbs function 576.5
  • Entropy 186.892
  • Heat Capacity 20.803

 Miscellaneous physical

• Electrical resistivity: 33.08 µ-ohms/cm
• Debye temperature: 252.0 K
• Thermal conductivity: 23.0 W / m / K
• Coefficient of linear expansion: 5.9Coef. per K
• Mass magnetic susceptibility: 5.3e-9
• X-ray diffraction mass absorption coefficients:
• CuK: 159 (µ/p)/cm2 g-1
• MoK: 91.7 (µ/p)/cm2 g-1

Hafnium Chemical Properties

 Chemical basics:

• Oxidation states: +4
• Molecular wt: 178.49 g/mole

 Radii

• Covalent: 144 pm
• Atomic: 159.0 pm
• Van der Waals: pm

 Ions:

• ion: +4 pm 71.0

 Covalent bonds

 Effective nuclear charge

• Slater: 3.15
• Clementi: 9.16
• Froese-Fischer: 13.27

 Electronegativity

• Pauling: 1.3
• Allred-Rochow: 1.23

 Standard reactions

Hafnium Nuclear Properties

• Known 19
• Listed 10

• Known 169 - 183
• Listed 172 - 182

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 1.87 years
  • Decay mode: E.C.,
  • Source:
• Notes

• % Occ.:Natural 0.162%
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 2.00 E15 years
  • Decay mode: alpha,
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 70.00 days
  • Decay mode: E.C.,
  • Source:
• Notes

• % Occ.:Natural 5.206%
• Mossbauer NRA: 14.2
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 18.606%
• Mossbauer NRA: 18.1
• Nuclear spin/Quantum no.: 7/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 27.297%
• Mossbauer NRA: 14.9 *
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 13.629%
• Mossbauer NRA:
• Nuclear spin/Quantum no.: 9/2
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural 35.100%
• Mossbauer NRA: 14.9
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life:
  • Decay mode:
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 42.40 days
  • Decay mode: Beta-
  • Source:
• Notes

• % Occ.:Natural
• Mossbauer NRA:
• Nuclear spin/Quantum no.:
• Radioisotopes:
  • Half-life: 9.00 E6 years
  • Decay mode: Beta-
  • Source:
• Notes

• Isotope Cross-section 103±3 barns

• Absolute sensitivity: 1.18e-4 1H=1.0
• Relative sensitivity: 6.38e-4 1H=1.0
• Receptivity: 0.88 13C=1.0
• Magnetogyric ratio: 0.945e7 rad / T / s
• Quadropole moment: 4.5e-28 m2
• Frequency: 3.120 MHz
• Reference:

Hafnium Energy Properties

Electrons

• Ground state electron configuration: [Xe] 4f14 5d2 6s2
• Electron affinity: -61 kJ mol-1
• Filling orbitals:

Spectral lines

 Ionization energies

 Atomic energy levels