The solubility products of 32 metallic carboxylates resulting from the precipitation of seven cations (Cd, Co, Cu, Mn, Ni, Pb, and Zn) with six linear saturated carboxylates (heptanoate, octanoate, nonanoate, decanoate, dodecanoate, and octadecanoate) are reported. Solubility measurements were performed using the analytical method with freshly precipitated metallic carboxylates. From the measured metal concentration and equilibrium pH value, solubility products, K-sp, were determined. The results indicate a linear relationship between the negative logarithm of the solubility product and the carbon number in the aliphatic chain that is valid from 7 to 12 carbons. The determination of the pK(sp) value of copper octadecanoate shows the limit of the linear model. Indeed, the experimental value obtained demonstrates that pK(sp) tends to a limiting value and becomes independent of the chain length.