Hafnium

| Introduction | History | Other Periodic Tables | Back |

Symbol:

Hf

Atomic Number:

72

Relative Atomic Mass:

178.49 g mol^-1

Natural Abundance in Lithosphere, hydrosphere and atmosphere:

4 x 10^-4% (mass fraction)

Electron Configuration:

[Xe]4f¹⁴5d²6s²

Oxidation States:

IV

Atomic Radius:

156.4pm

Covalent Radius:

144pm

Ionic Radius:

71pm (for +4 oxidation state, 4 coordinate)

76pm (for +4 oxidation state, 6 coordinate)

Melting Point:

2227°C

Density:

13.31 g cm^-3 (at 20°C)

First Ionisation Energy:

7.0 eV

Reduction Potential:

-1.505V

for HfO₂ + 4H⁺ + 4e^- a Hf_(s) + 2H₂O

Electronegativity (Allred and Rochow):

1.2

Number of Natural Isotopes:

6

Mass Number of the Most Abundant Isotopes:

177 g mol^-1 a 18.6% abundance

178 g mol^-1 a 27.3% abundance

180 g mol^-1 a 35.1% abundance