Abstract: COORDINATION HYDROLYSIS BEHAVIOUR OF PALLADIUM(Ⅱ) IN CHLORIDE MEDIAHuang Xiwen Cong Peijun Zhu Bintuan Wang Rongshu(Department of Chemical Engineering,Tianjin University,Tianjin 300072)ABSTRACTThe coordination hydrolysis behavior of Pd2＋ has been examined in chloride media solution by ultraviolet absorption spectrograph.The results indicate that although the high pH values of solution could promote the hydrolysis of Pd2＋,the hydrolysis procedure is strongly suppressed by the chloridepalladium coordination compound (PdCli)2－i(i=0—4) formed in the solution with a high concentration of chloride media.When the pH values of solution are less than 8.0,the hydroxy coordination compound accounted for less than 10% of the total palladium and the remainder is present principally as PdCl2－4. By use of the model equation derived from the coordination hydrolysis of Pd2＋,the distribution of various Pd2＋ species between pH6.0 and 10.0 is obtained. It is shown that only when the pH values are more than 8.5,the hydroxypalladium coordination species could be dominant over the major chloride coordination compound PdCl2－4.Key words Palladium Coordination hydrolysis Palladium coordination compound Ultraviolet absorption spectrograph