What is the structure of Fe at core P and T?
High P/T phase of Fe is controversial.
Boehler 1993 observed a possible new phase in DAC above ~40 GPa and ~1000 K.
Andrault et al claim an orthorhombic phase.
Saxena et al suggest dhcp.
Shen et al fail to find it.
Brown & McQueen shock expts. claim a solid-solid phase change ~200 GPa and ~4000 K.
Nguyen and Holmes donít find it!