SYNTHESIS AND THERMAL-DECOMPOSITION OF SOME RARE EARTH(III) DIMETHYLAMMONIUM SULFATE CRYSTALLOHYDRATES .2. RESULTS OF INVESTIGATIONS OF [(CH3)2NH2]3LN(SO4)3.3H2O
Vb. Jordanovska et J. Siftar, SYNTHESIS AND THERMAL-DECOMPOSITION OF SOME RARE EARTH(III) DIMETHYLAMMONIUM SULFATE CRYSTALLOHYDRATES .2. RESULTS OF INVESTIGATIONS OF [(CH3)2NH2]3LN(SO4)3.3H2O, Thermochimica acta, 221(1), 1993, pp. 79-84
Double sulphates of rare earths(III) with dimethylammonium were obtain
ed by evaporation of aqueous reaction mixtures of rare earth(III) sulp
hates and dimethylammonium sulphate in molar ratios greater than 1:20.
By means of X-ray powder diffraction patterns, it was found that they
are isostructural. From the TG curve of the thermal decompositions of
the obtained compounds in the temperature interval from 20 to 700-deg
rees-C, their general empirical formula was established as [(CH3)2NH2]
3Ln(SO4)3 . 3H2O (where Ln is Nd, Sm, Eu, Gd, Tb). The thermal decompo
sition of the anhydrous double salts takes place with thermal effects
on the DTA curve, which means that this process is not a simple dissoc
iation, but that intermediate products are possibly involved. The equa
tions of the thermal decomposition are also presented.