Thermaldecomposition of hydrotalcitewith hexacyanoferrate(II) and hexacyanoferrate(III)anions in the interlayer

The thermal decompositions of hydrotalcites with hexacyanoferrate(II) and hexacyanoferrate(III) in the interlayer have been studied using thermogravimetry combined with mass spectrometry. X-ray diffraction shows the hydrotalcites have a d(003) spacing of 11.1 and 10.9 Å which compares with a d-spacing of 7.9 and 7.98 Å for the hydrotalcite with carbonate or sulphate in the interlayer. XRD was also used to determine the products of the thermal decomposition. For the hydrotalcite decomposition the products were MgO, Fe₂O₃ and a spinel MgAl₂O₄. Dehydration and dehydroxylation take place in three steps each and the loss of cyanide ions in two steps.