Pressure-Induced sp(2)-sp(3) Transitions in Carbon-Bearing Phases

Carbon-bearing phases show a rich variety of structural transitions as an adaptation to pressure. Of particular interest is the crossover from sp(2) carbon to sp(3) carbon, as physical and chemical properties of carbon in these distinct electronic configurations are very different. In this chapter we review pressure-induced sp(2)-sp(3) transitions in elemental carbon, carbonates, and hydrocarbons.