The thermal decomposition reactions of the following chromium(III) complexes were investigated:Cr(CH3COO)3 "2 H20, [Cr30(CH3COO)6(H20)3]CI "2 H20 and [Cr30(CH2CICOO)6(H20)3]CI'6H20. Simultaneous TG/DTG/DTA were applied nonisothermal conditions. From the recorded curves, the activation energies Ea were calculated for all the thermal decomposition steps. Appropriate chemical reactions were attributed to the thermal effects, with consideration to the X-ray diffraction and IR spectra results.The coordination compounds are subject to ever increasing research by derivatography because of the various molecular structures of these compounds and the great variety of ligands and central ions, and also because of the role played by coordination compounds and their high-temperature decomposition products in catalytic processes. Application of derivatography may also provide qualitative information regarding the stability of the crystal lattice, the character of the bonding in the molecules, the mechanism of their decomposition and the kinetics of these reactions. Obviously, this research must be related with the results of other structural investigations, e.g. X-ray crystallography or spectroscopy. This work presents the results of such studies on the following compounds:Cr (CH3COO)3" 2 H20, [Cr30(CH2C1COO)6(H20)3]C1-2 H20 and [CraO(CH3COO)6(H20)3]CI" 6 H20.

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In this paper the results of comparative thermal analysis TG-DTG-DTA-DSC for the thermal decomposition process of [Cr(NH3)~ilC13 in air atmosphere are given. The kinetics and mechanism of this complex thermal decomposition, process enthalpy as the changes of specific thermal capacity of solid products reaction with temperature were determined.Numerous authors were studied thermal stability of hexamminechromium(III) chloride [1][2][3]. The deamination reaction for [Cr(en)3]C13 occurs at 260 ~ although the similar complex with ethulamine is less stable no DTA curve is known to the author [1]. It is interesting to note that [Cr(NH3)6]CI3 is just as stable as [Cr(en)3]C13. The initial reaction, however, is more severe in the decomposition of the amine complex, which loses three molecules of NH3 to give [Cr(NH3)3]C13 at 280 ~ whereas the ethylenediamine complex loses only one molecule of ethylenediamine [2][3]. The electric features of this type chrome compound were studied by Grotovska and Wojcichowski [4].In this paper is given a contribution to the comparative study of thermal decomposition process of hexamminechromium(III)chloride by use of DTA-TG-DTG simultaneous analysis as well as by use of DSC measurements of process enthalpy and Cp change (specific thermal capacity) of solid products reaction, developed during thermal decomposition process.

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