Hydrotalcite-like compounds obtained by anion exchange reactions

The synthesis of nickel aluminium hydroxypicrate, [Ni3Al(OH)8] (C6O7N3H2)·nH 2O, and lithium aluminium hydroxypicrate, [Al2Li(OH)6] (C6O7N3H2)·nH 2O by anion exchange is described. Picric acid and the corresponding hydroxycarbonates were used as starting materials. The new compounds were characterized by chemical analyses, electron microscopy, infrared spectroscopy and X-ray diffraction. The results obtained indicate that both are hydrotalcite-like compounds where the picrate anion lies between the basic layers. The thermal decomposition of the compounds was studied by differential thermal and thermogravimetric analysis.