The lighter group-V element phosphorus forms the As-type (hR2) structure under pressure, above 5 GPa, and at 10 GPa transforms to the simple cubic structure (cP1), similar to arsenic. Despite of its low packing density, the simple cubic structure is stable in phosphorus over a very wide pressure range up to 103 GPa. On further pressure increase, the simple cubic structure transforms to a simple hexagonal structure (hP1) via a complex phase that was solved recently as incommensurately modulated. Structural transformations of Phosphorus are connected with the changes of physical properties. Above 5 GPa phosphorus shows superconductivity with Tc reaching ~9.5K at 32GPa. The crystal structures and properties of high-pressure phases for Phosphorus are discussed within the model of the Fermi sphere and Brillouin zone interactions.
