2. Equations of state for solids under high compression

As mentioned in the article dedicated to liquids, bond types are usually classified into four categories: covalent, ionic, metallic and molecular, but in reality they are more often variable combinations of these four types, depending on pressure and temperature conditions. Covalent solids (e.g. diamond) and ionic solids (e.g. silica) are the most strongly bonded and therefore the least compressible. As in the case of liquids, the thermodynamic behavior of solids under pressure is completely governed by their equation of state.