Siderophile Elements
Siderophile elements are 'iron-loving' chemicals that bond strongly with iron and sink into a planet's core during its formation, including gold, nickel, and platinum.
Siderophile elements are a class of chemical elements that exhibit a strong affinity for iron, particularly under high-temperature conditions found during planetary differentiation. These elements, such as gold, nickel, and platinum, tend to segregate into the iron-rich core of a planet rather than remaining in the crust or mantle. The term derives from the Greek 'sideros' (iron) and 'philos' (loving).
What this means in real life
When Earth formed, nickel and cobalt—both siderophile elements—sank with molten iron toward the planet's core rather than staying in the rocky mantle, which is why Earth's core is an iron-nickel alloy.
What it isn’t
These are not elements that are simply attracted to magnets or magnetic in nature. Siderophile refers specifically to chemical affinity and bonding preference for iron during planetary differentiation, not magnetic properties.
Commonly misused online
Often conflated with 'iron-loving' in a loose sense; some posts treat it as synonymous with 'magnetic' or assume all siderophile elements are rare or precious, when many are actually common industrial metals.