Which Elements Fused Together to Form Iron?

Answer: After the hydrogen in the star's core is exhausted, the star can fuse helium to form progressively heavier elements, carbon and oxygen and so on, until iron and nickel are formed.

What are the elements up to iron?

These elements are Neon, Sodium, Magnesium, Sulfur, Silicon, Nickel, Cobalt and Iron.

Why can iron be fused?

Even higher mass stars will burn neon after carbon is used up. However, once iron is reached, fusion is halted since iron is so tightly bound that no energy can be extracted by fusion. Iron can fuse, but it absorbs energy in the process and the core temperature drops.