Authors:M. Ji, J. Liu, S. Gao, B. Kang, R. Hu, and Q. Shi
The enthalpies of solution in water of RE(His)(NO3)3
H2O (RE=La—Nd, Sm—Lu, Y) were measured calorimetrically at 298.15 K, and the standard enthalpies of formation of RE(His)aq3+ (RE=La—Nd, Sm—Lu, Y) were calculated. The plot of the enthalpies of solution vs. the atomic numbers of the elements in the lanthanide series exhibits the tetrad effect.
Authors:Angela Martins, João M. Silva, Fernando Râmoa Ribeiro, and M. Filipa Ribeiro
obtained by performing three consecutive ion exchanges with 1.5 M NH 4 NO 3 at 80 °C for 6 h each, followed by calcination at 500 °C under air flow. A portion of the synthesized zeolite was submitted to ion exchange with rareearthnitrate solutions (RE
Authors:Hiléia K. S. Souza, V. R. da Silveira, F. M. M. Borges, Dulce M. A. Melo, H. Scatena Jr., O. A. de Oliveira, and A. G. Souza
Thermal behavior of rare earth nitrate complexes with 2-azacyclononanone (AZA) with Ln(NO3)3·3(AZA) composition (where Ln=Gd, Er and Ho) was analyzed in kinetic point of view. Kinetic parameters were calculated from thermogravimetric data. All obtained results were similar. The first decomposition step was representative to the loss of ligand and the residue was essentially Ln2O3. Furthermore, a reaction path was proposed for the thermal decomposition of the Ln(NO3)3·3(AZA).
The principal steps in a well-tested procedure for analysis of the rare earths in rocks and minerals are: irradiation of powdered
rock samples along with a standard solution mixture of rare-earth nitrates; dissolution of the rock powder in the presence
of carrier, using Na2O2 fusion; separation of the rare-earth group from the silicate residue by a sequence of hydroxide and oxalate precipitations;
separation of the individual rare earths in samples and irradiated standards by ion exchange; chemical yield determination
by EDTA titration; radioassay by beta or gamma counting. The average precision for duplicate analyses by different analysts
was found to be better than ±4 percent mean deviation for a shale with a total rare-earth content of 200 ppm.
Authors:Esra Korkmaz and Nilgun Ozpozan Kalaycioglu
ratio of one mol of magnesium nitrate (Mg(NO 3 ) 2 ·6H 2 O) (A.R.) and one mol of tetra- n -butyl titanate (Ti(OC 4 H 9 ) 4 ) (A.R.) and 0.01 or 0.1 mol of rare-earthnitrate of 99.99% purity in an air atmosphere. The chemicals weighted ground well in