Abundances (with respect to H₂) of SiC and SiC₂, and Mg- or Fe-bearing species involved in the formation of metallic clusters as a function of radius. Abundances derived by thermodynamic equilibrium at r_s are moved to radius 1 R_⋆ for clarity. Except for SiC₂ and metal sulphide cluster precursors, abundances are quite low in the dust formation zone, and pure metal clusters do not form from the gas phase.