The relationship between temperature, pressure, and the phase of a substance can be represented using a phase diagram. Phase diagrams can be complex; sometimes several different condensed phases are possible for a substance. For example, diamonds and graphite are different possible phases for the element carbon.

Solids also have vapor pressures. These curves are shaped similarly to those of liquids. At temperatures below the melting temperature, the vapor pressure of the solid is lower than that of the liquid. Above the melting temperature, the vapor pressure of the solid is higher than that of the liquid.

FSU site for phase diagrams.