THE 2D RANCIEITE-TYPE MANGANIC ACID AND ITS ALKALI-EXCHANGED DERIVATIVES .1. CHEMICAL CHARACTERIZATION AND THERMAL-BEHAVIOR

The 2D Rancieite type manganic acid was prepared by reduction of KMnO4 in acidic medium. Its ion exchange behavior allows to prepare alkali derivatives. All compounds were characterized with use of a combinatio n of X-ray diffraction, chemical analyses, TGA, magnetic measurements and spectroscopic techniques. The evolution of their chemical composit ion versus temperature was studied between 180 and 400 degrees C. It s hows that the dehydration process is partly reversible in these compou nds whereas the weak reduction is irreversible. The 2D Rancieite-type manganic acid is readily different from a Birnessite-type phyllomangan ate, as shown by several features: the interlayer distance, the ion ex change capacity, the thermal behavior, the interlayer cation content, the manganese average oxidation state, the magnetic behavior and the I R spectrum.