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Modifications of dithiocyanatodiammine copper (II) complex. II. Investigation of properties of modifications of dithiocyanatodiamminecopper(II) by thermal analysis

H. Langfelderová, M. Kabešová, J. Garaj, and J. Gažo

Department of Inorganic Chemistry, Slovak Technical University, Bratislava


Abstract: In the present work the thermic properties of the modifications of the dithiocyanatediamminecopper( II) complex are studied; further it is investigated how far high pressure and fine grinding change the thermic properties of the samples. I t has been found that the thermograms of the modifications of Cu(SCN)2(NH3)2 — which have been prepared by crystallization from water solution — differ in the range between 200—300 °C; these modifications can be divided into three groups. Whereas the thermogravimetric analysis yields identical results for these three groups, t h e character of the DTG curves indicates that the decomposition mechanism is not the same in all three groups. This division, however, does not agree with our classification of these groups performed on the basis of the diffraction data. The fourth group of thermograms are those made with samples submitted to high pressures and fine .grinding. The DTA curves of these samples differ from the above mentioned curves in the number of endo thermic peaks: whereas on the DTA curves of the afore mentioned three groups of modifications there is one endothermic peak at 150—160 °C, in the fourth group a further peak at 100—110°C is observed. The decomposition temperature of these samples (the fourth group) is considerably lowered. Thermogravimetric curves of samples submitted to high pressures and fine grinding are not identical. This method of preparation of the samples also influences the values of the comparison factors. Through fine grinding these values are shifted in the range of a-modifications, under the influence of high pressure they get near 1. We assume that these mechanic actions bring about structural changes of not exactly known character and these cause the lowering of thermic stability.

Full paper in Portable Document Format: 221a42.pdf (in Slovak)


Chemical Papers 22 (1) 42–49 (1968)

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