The effect of increasing concentrations of the organic chelating agents EDTA, DTPA and Citrate ( at concentration ranging from 0.005 M and 0.1 M ) on the solubility of Nickel in 95% saturated calcium hydroxide solutions have been investigated as well as the possibility of the formation of Multi-Metal ligand complexes [Ca-Ni-Ligand] by study the effects of increasing concentrations of the calcium hydroxide on the solubility of Nickel in presence of fixed concentrations of the organic ligands in saturated sodium hydroxide .