* Face-centered cubic (FCC): This is the stable structure at room temperature and above. It's also known as the α-phase of cobalt.
* Hexagonal close-packed (HCP): This structure is stable below about 420°C and is known as the β-phase of cobalt.
It's important to note that the transition between these two structures is gradual, meaning that a mixture of both phases can exist within a certain temperature range.
