The complexation of trivalent actinides (An(III)) with chloride is studied in the temperature range from 25 to 200 degrees C by spectroscopic methods. Time-resolved laser fluorescence spectroscopy (TRLFS) is applied to determine the thermodynamic data of Cm(III)-Cl- complexes, while extended X-ray absorption fine structure spectroscopy (EXAFS) is used to determine the structural data of the respective Am(III) complexes. The experiments are performed in a custom-built high-temperature cell which is modified for the respective spectroscopic technique. The TRLFS results show that at 25 degrees C the speciation is dominated mainly by the Cm3+ aquo ion. Only a minor fraction of the CmCl2+ complex is present in solution. As the temperature increases, the fraction of this species decreases further. Simultaneously, the fraction of the CmCl2+ complex increases strongly with the temperature. Also, the CmCl3 complex is formed to a minor extent at T > 160 degrees C. The conditional stability constant log beta(2)' is determined as a function of the temperature and extrapolated to zero ionic Strength with the specific ion interaction theory approach. The log beta(2)degrees(T) values increase by more than 3 orders of magnitude in the studied temperature range. The temperature dependency of log beta(2)degrees is fitted by the extended van't Hoff equation to determine Delta H-r(m)degrees, Delta S-r(m)degrees, and Delta C-r(p,m)degrees. The EXAFS results support these findings. The results confirm the absence of americium(III) chloride complexes at T = 25 and 90 degrees C ([Am(III)] = 10(-3) m, [Cl-] = 3.0 m), and the spectra are described by 9-10 oxygen atoms at a distance of 2.44-2.48 angstrom. At T = 200 degrees C two chloride ligands are present in the inner coordination sphere of Am(III) at a distance of 2.78 angstrom.