Hafnium (Hf)
Hafnium is element 72, a transition metal in period 6, group 4 of the periodic table. At room temperature it is a solid.
Electron configuration [Xe] 4f14 5d2 6s2
Electrons per shell 2, 8, 18, 32, 10, 2
Hafnium data
| Atomic number | 72 |
|---|---|
| Symbol | Hf |
| Atomic mass | 178.49 u |
| Category | Transition metal |
| Group | 4 |
| Period | 6 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 2506 K (2232.9 °C) |
| Boiling point | 4876 K (4602.9 °C) |
| Density | 13.31 g/cm³ |
| Electronegativity (Pauling) | 1.3 |
| Atomic radius | 150 pm |
| 1st ionization energy | 659 kJ/mol |
| Electron affinity | 0 kJ/mol |
| Oxidation states | +2, +3, +4 |
| Common ion charge | 4+ |
| Discovered | 1923 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through hafnium’s configuration and its ions →
Where hafnium sits
Hafnium belongs to the transition metals. Its Pauling electronegativity of 1.3 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Hafnium FAQ
What is the electron configuration of hafnium?
Hafnium (Z = 72) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d2 6s2. In noble-gas shorthand that is [Xe] 4f14 5d2 6s2.
How many valence electrons does hafnium have?
4 (2 outer s + 2 d electrons; 2 in the outermost shell).
What is the atomic mass of hafnium?
The standard atomic weight of hafnium is 178.49 u, so one mole weighs 178.49 g.
Is hafnium a metal?
Yes. Hafnium is a transition metal.
What is the charge of a hafnium ion?
Hafnium most commonly forms Hf4+.