For heterogeneous equilibria (several phases, gaseous phase> liquid phase> solid phase), the species involved in the upper phase are kept in equilibrium constants only: for instance: $aA(s) + bB(l)\leftrightarrows cC(l) + dD(l)$ $K\;=\;\frac{[C]^c[D]^d}{[B]^b}$ $aA(g) + bB(l)\leftrightarrows cC(l) + dD(g)$ $K_p\;=\;\frac{p_D^d}{p_A^a}$ $K\;=\;\frac{[D]^d}{[A]^a}$