  Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe
clouds. The ionisation equilibrium equations were used to model the column
densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The
chemical composition of CaFe clouds is that of the Solar System and no
depletion of elements onto dust grains is seen. The CaFe clouds have high
electron densities n=1 cm^-3 that leads to high column densities of neutral Ca
and Fe.
