# How many components and phases are in an equilibrium system comprising lead sulfate, lead ions, and sulfate ions?

I am going to calculate the degrees of freedom ($F = C-P+2$) on the following system, but I can't figure out whether we have to take $\ce{PbSO4}$, $\ce{Pb^2+}$ and $\ce{SO4^2-}$ as a single component and single phase, or $\ce{PbSO4}$ and $\ce{Pb^2+}$, $\ce{SO4^2-}$ as 2 components and 2 phases?