Geometric structure, high pressure chemical

It has been known for many decades that different crystal faces of the same element display subtly different chemical properties. This could be for a number of reasons, including differences in the electronic band structure at the surface, or due to the fact that different structures stabilize different intermediates or transition states to different extents for geometrical reasons. Clearly this is an important issue in catalysis, but maintaining the crystal faces in a clean, well-defined state before the reaction (which might be at high pressure) has been a challenge to many researchers in this field. 

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