No abstract

No abstract

No abstract

The processes of thermal dehydration and decomposition of Mn(NOs)2".6H20 and its deuterated analogue were studied by DTA, TG and DSC. Comparisons were made between the data obtained for the two compounds. The following phase transitions were observed: melting of the compound; dehydration to monohydrate; dehydration of the monohydrate, accompanied by its partial decomposition to MnO2; and decomposition of the anhydrous nitrate to MnO2.The DSC data were used to determine the enthalpies of the phase transitions, and those corresponding to the partial dehydration were compared with the calculated ones. The formal kinetic parameters (E* and A) for the three stages (without the melting stage) were calculated from the TG curves, and the corresponding kinetic equations are reported.The pertinent literature contains data about the thermal decomposition of aqueous solutions of Mn(NO2)2. According to [1][2][3], for instance, the water is evaporated until the formation of a solution containing Mn(NO3)2 and H20 in a mole ratio of 1:1, whereas [4,5,9,10] give this mole ratio as 1:2. This is followed by decomposition of the nitrate to MnO2, which according to [1,2,4,9] [10]. The thermal decomposition of Mn(NO3)2"6H20 has been studied in [8], with the authors describing fusion of the salt, dehydration to Mn(NO3)2.1.7H20 and decomposition to MnO2.All authors report MnO2 as the end-product of the thermal decomposition, but according to [10] it contains impurities of Mn203.

Phase relationships and therm al decomposition of beryllium iodates and periodates were studied by X-ray and spectroscopic (IR, Ram an) measurements. B e(I03)2-4 H 20 , B e(I03)2, and Be(H4I 0 6)2-4 H 20 have been characterized. Be(H4I 0 6)2-4 H 20 (hitherto claimed in the lit erature to be a metaperiodate) dehydrates on heating with decomposition to form B e(I03)2. Anhydrous beryllium periodate was not obtained. On dehydration of B e(I0 3)2-4 H 20 , an hydrous B e(I03)2 is formed, which decomposes into BeO, I2, and 0 2 on further heating.