Dynamic compression of SiO₂: A new interpretation

In light of recent discoveries of post‐stishovite phases of SiO 2 , with the CaCl 2 and α‐PbO 2 structures, we have reassigned the regimes along the Hugoniots for initial quartz, coesite, cristobalite, porous coesite, and fused silica. Calculated Hugoniots for fused silica, cristobalite and porous coesite indicate transition to stishovite, and then melt. Hugoniots for crystal quartz and coesite indicate that transition occurs to stishovite, then the CaCl 2 structure and finally to melt.