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Here we report a review of the results of our studies in recent years on reactions of coordination compounds in solid state at ordinary ard medium temperatures. The studies have been made mainly by means of gas chromatography coupled with various spectroscopic methods. The results are described with respect to the following aspects

The thermal decomposition of K 3 Co(CN) 5 L (L = CN − , NO 2 − , N 3 − , NO) in a hydrogen atmosphere has been studied by gas chromatography. The first stage of thermal decomposition of these complexes is to release crystal water if contained, and the second stage is to dissociate the ligand at very high speed, with a large amount of heat being released when LN 3 − . Thirdly, the residual cyano-cobalt complex is further decomposed to form HCN, (CN) 2 and N 2 and a little NH 3 and CH 4 . In the presence of iron powder, the evolution of NH 3 is increased greatly, whereas HCN disappeared entirely. The influence of reduced iron powder upon the decomposition is also studied.

The solid state reaction of sodium nitrate and iron (III) oxalate in hydrogen atmosphere was investigated by gas chromatography, Mossbauer spectroscopy and X-ray diffraction. The results show that there is no reaction below 240°C between them while iron (III) Oxalate decomposes itself into α-FeC2O4 and gives off CO2 and H2O peaks at 180°C. The reaction takes place at 260—300°C when sodium nitrate oxidizes α-FeC2O4 to Fe (III) compound and releases large amount of CO2 and a little NO and O2. Different mole proportions and particle sizes of reactants have no obvious effect on solid state reaction. Because of the catalyzing effect of Fe (III) compound, sodium nitrate and its reduction product, sodium nitrite decomposes at 380—500°C and Fe (III) compound is transformed into γ-Fe2O3 at 460°C.

Some properties and thermal decomposition of iron (III) oxalate supported on HZSM-5 and HY zeolites have been studied by GC, IR, and Mossbauer spectroscopy methods. Thermal decomposition of unsupported iron (III) oxalate took place in two stages: as indicated by peak α (giving CO2) and peak γ (yielding CO and CO2), but for iron (III) oxalate supported on zeolites, an additional peak β (producing CO and CO2) appeared as a result of the interaction between C2O42− and Al3+. At 500°C Fe2(C2O4)3-HZSM-5 system produced α-Fe in H2 due to the weak interaction between the salt and the support. For Fe2(C2O4)3-HY system in H2, at 500° the solid products consisted of α-Fe and a little highly dispersed Fe (0) together with Fe (II) and F(III) oxides, which were difficult to be reduced.