Hafnium (Hf)
| Atomic Number | 72 |
|---|---|
| Atomic Mass | 178.492 u |
| Category | Transition metal |
| Electron Config | [Xe] 4f¹⁴ 5d² 6s² |
| Appearance | steel gray |
| Density (STP) | 13310 g/L |
| Melting Point | 2506 K |
| Boiling Point | 4876 K |
| Electronegativity | 1.3 (Pauling) |
| Ionization Energy | 658.5 kJ/mol |
| Atomic Radius | 155 pm |
| Crystal Structure | Simple Hexagonal |
| Discovered By | Dirk Coster (1923) |
Brief Introduction
Hafnium (Hf) is a lustrous, silvery-gray, ductile transition metal, highly corrosion-resistant due to a protective oxide layer. Primarily used for control rods in nuclear reactors—due to its excellent neutron absorption—and in high-temperature superalloys for aerospace. It is found in zircon minerals and is produced as a byproduct of zirconium refining. Key details about Hafnium (Hf) are as follows:
Uses: Due to its high melting point (2233°C) and neutron absorption, it is used for nuclear control rods, vacuum tube getters, and in semiconductor manufacturing (chips).
Production/Extraction: It is always found with zirconium. Because it is chemically similar, it is extremely difficult to separate. It is typically produced as a byproduct of zirconium refining from zircon sand.
History: Predicted by Mendeleev in 1869, it was not officially discovered until 1923 by Dirk Coster and Georg von Hevesy in Copenhagen, Denmark (named after Hafnia, the Latin name for Copenhagen).
Health Effects & Safety: While not considered highly toxic, fine hafnium powder is highly flammable and poses a fire hazard. It can be found in traces in human saliva and urine.
Price/Market: Considered a critical mineral for defense and nuclear applications, which drives its economic value.
Properties: It has a high density and is very resistant to acids and alkalis. It forms a very high-melting compound, hafnium carbide (HfC), with a melting point over 3,890°C.
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