Clapeyron pressure relation for equal-density phases
= Clapeyron pressure relation for equal-density phases
{c}
{title2=$p_s-p_l=\rho L(T_m-T_i)/T_m$}
= Thermomolecular pressure relation
{synonym}
For equal solid and liquid <mass densities>, $d\mu=-s\,dT+dp/\rho$ and $s_l-s_s=L/T_m$ imply the displayed relation from equality of <chemical potentials>. $T_m$ must be absolute <temperature>. The phase pressures differ; this should not be confused with differentiating a coexistence curve along a common pressure.