In the structure of lactoferrin, the iron ion is buried inside the protein.

The large semi-transparent sphere indicates the location of the iron ion.

In the presence of oxygen and water, they rapidly oxidize to form free iron ions.

Initially, this oxygen was absorbed by combining with iron ions in solution.

Haemoglobin, the main oxygen carrying molecule has a central iron ion.

The enhancement of the X-rays from iron ions would be due to this same effect.

The active sites of most isopenicillin N synthases contain an iron ion.

It is an iron ion in the center of a large organic ring called a porphyrin.

The blood's red color is due to the spectral properties of the hemic iron ions in hemoglobin.

IscA is able to bind at least 2 iron ions per dimer.