SYNTHESIS AND THERMAL-DECOMPOSITION OF SOME RARE EARTH(III) DIMETHYLAMMONIUM SULFATE CRYSTALLOHYDRATES .1. RESULTS OF INVESTIGATIONS OF (CH3)2NH2LN(SO4)2.H2O (WHERE LN IS LA-GD)
Vb. Jordanovska et J. Siftar, SYNTHESIS AND THERMAL-DECOMPOSITION OF SOME RARE EARTH(III) DIMETHYLAMMONIUM SULFATE CRYSTALLOHYDRATES .1. RESULTS OF INVESTIGATIONS OF (CH3)2NH2LN(SO4)2.H2O (WHERE LN IS LA-GD), Thermochimica acta, 221(1), 1993, pp. 73-78
The double sulphates of some rare earths(III) with dimethylammonium we
re obtained as crystalline products by evaporation at room temperature
of an aqueous mixture of Ln(III) sulphate and dimethylammonium sulpha
te in molar ratio from 1:4 to 1:15, and treatment, in some cases, of t
he concentrated mixture with ethanol. The identification was carried o
ut by means of X-ray powder diffraction patterns. It was found that th
ey are isostructural. On the basis of the thermal decomposition and ch
emical analysis of the obtained double salts, their general empirical
formula (CH3)2NH2Ln(SO4)2 . H2O was established. It was found that rar
e earth(III) sulphates are obtained at 700-degrees-C. The thermal deco
mposition takes place in two well-resolved stages. The decomposition o
f the anhydrous double salts is not a simple dissociation, but involve
s intermediate reactions.