The Cd(II)-dipicolinic acid (pyridine-2,6-dicarboxylic acid) system was studied by polarography in the temperature range (298 to 313) K and ionic strength of (0.25 to 0.5) mol . dm(-3) (H,K)NO3. Apart from detecting the already reported ML and ML2 complexes and reporting the log beta values at T = (298, 305 and 313) K, an ML3 complex was also found to form at 40 degrees C giving a log beta value of 13.5 +/- 0.1. ML3 was not present to a significant extent at lower temperatures indicating an endothermic formation process. This finding is supported by the ML3 structure being reported for crystals grown at T = 313 K. The system was also studied from pH 1 using protocols developed employing Tl(I) as an internal reference. The MLH species was found in the low pH range with log beta values of 8.4 +/- 0.2, 8.2 +/- 0.2 and 8.0 +/- 0.1 found at T = (298, 305 and 313) K, respectively. (C) 2015 Elsevier Ltd. All rights reserved.