Abstract: The hydrolytic polymerization of Cr³⁺ at rather high concentrations was studied pH-metrically. Four series of chromic nitrate solutions have been prepared of 0.160M, 0.200M,0.250M and 0.320M concentration, each with various pH and all with 0.5M sodium nitrate. The solutions were hold in polyethylene bottles and kept at 40±1℃. From time to time, a small portion of each solution was taken and its pH was measured at 30±0.1℃. When difference between the pH values measured over an interval of four days was less than 0.005 pH, equilibrium was considered to be established, which usually took about one month.The values of Z, the average number of OH- bound per Cr³⁺ ,were calculated at different pH. The highest value of Z was about 0.5 for solutions of concentration higher than 0.160M which had Z of about 1.0. Then the Z vs. pH curve was plotted for each concentration, B, The fact that the curves of different concentrations did not coincide but separated from each other indicated that polynuclear coordination compounds had been formed. When B and pH of the same Z from dif-. ferent curves of (Z vs. pH)_B were plotted, a linear relationship between -IgB and pH was found. Hence the hydrolytic polymerization reaction took place according to the "core + links" scheme and the product could be represented as Cr[Cr(OH)_t]_n^(3+n(3-t))+, t being the slopes of the straight lines, (-∂lgB/∂pH)_B, which is about 1.0 in the region of Z studied. This was the type of"core+links"compound when Cr³⁺ concentrations was 0.160-0.320M. At lower concentration, t = 2 as reported in part (Ⅰ) of this series of studies.Under the present experimental conditions, n, the number of links in Cr[Cr(OH)]_n(3+2n)+ was determined to be 1 and 2 , and the hydrolysis constants obtained are as follows; lgβ_1,2 = -2.68, lgβ_2,3 =-3.84.