The chemical symbol for Hafnium is Hf and its atomic number is 72.
We find it listed in the periodic table in Group 4 and 6 period and block.
The Hafnium belongs to the family or chemical series of transition metals such as for example the Silver, the Bohrium, cadmium, ...
This element is stable.
Hafnium came from the city name Hafnia.
Atomic number (Z) 72
Group, block group 4, d-block
Period: period 6
Element category: transition metal
Standard atomic weight (±) (Ar): 178.49(2)
Electron configuration: [Xe] 4f14 5d2 6s2
per shell: 2, 8, 18, 32, 10, 2
Physical properties
Phase: solid
Melting point: 2506 K (2233 °C, 4051 °F)
Boiling point: 4876 K (4603 °C, 8317 °F)
Density near r.t.: 13.31 g/cm3
when liquid, at m.p. 12 g/cm3
Heat of fusion: 27.2 kJ/mol
Heat of vaporization: 648 kJ/mol
Molar heat capacity: 25.73 J/(mol•K)
Atomic properties
Oxidation states: 4, 3, 2, 1, −2 (an amphoteric oxide)
Electronegativity: Pauling scale: 1.3
Ionization energies 1st: 658.5 kJ/mol
2nd: 1440 kJ/mol
3rd: 2250 kJ/mol
Atomic radius empirical: 159 pm
Covalent radius: 175±10 pm
Crystal structure: hexagonal close-packed
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 nΩ•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: 1520–2060 MPa
Brinell hardness: 1450–2100 MPa
CAS Number 7440-58-6