The study of materials under pressure is important to understand geophysical and astronomical processes but has also technological implications, for instance due to the possibility of creating new phases which might be stable at ambient conditions, with improved characteristics. In particular, there are many studies of iron under pressure, given that iron is an element of relevance in multiple areas, including its role in the Earth’s core. Research using ab initio simulations [1], diamond anvil cells [2–4], and dynamic shock experiments [5] is achieving increasing understanding of iron phase changes at high pressure, but detailed understanding of the solid-solid phase transition occurring around 10–30 GPa is still lacking.