Hafnium is named after Hafnia, the Latin word for the city of Copenhagen in Denmark. It took a long time to distinguish hafnium from zirconium because the two elements are present together in crystals of the mineral zircon and their atoms are of similar sizes. Hafnium is used in powerful cutters that pierce metal objects with a hot stream of sparks. It is also used to manufacture ultra-small electronic products, only a few millionths of a millimeter wide, in microchips.
Summary of properties (Hf)
| Atomic weight | 178.486(6) |
| Discoverer (year) | Coster, Dirk & De Hevesy, George Charles (1923) |
| Natural form | metallic solid (hexagonal) |
| Electron configuration | [Xe] 4f 14 5d2 6s2 |
| Melting point (ºC) | 2150 |
| Boiling point (ºC) | 5400 |
| Abundance in earth's crust (ppm) | 3 |
| Isotope (abundance) | 174Hf (0.16), 176Hf (5.26), 177Hf (18.60), 178Hf (27.28), 179Hf (13.62), 180Hf (35.08) |
| Density g/cm3 | 13.31 |
| Van der Waals radius (pm) | 223 |
| Covalent radius (pm) | 164 |
| Electronegativity (Pauling) | 1.3 |
| Vaporization enthalpy (kJ/mol) | 661.10 |
| Enthalpy of fusion (kJ/mol) | 27.20 |
| Specific heat capacity (J/g·K) at 25ºC and 1 atm | 0.14 |
| Thermal conductivity (W/cm·K) at 25ºC and 1 atm | 0.230 |
| Oxidation state | +4 |
| Electron affinity (eV) | 0.01 |
| 1st Ionization potential (eV) | 6.8251 |
