Thermogravimetry study of Gd2O3 chlorination Kinetics and characterization of gadolinium oxychloride

F. POMIRO; G. G. FOUGA; GAVIRÍA J.P.; A. E. BOHÉ

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY

SPRINGER

Año: 2015 vol. 122

1388-6150

The reaction between Gd2O3(s) and Cl2(g) was studied in a high resolution thermogravimetric system. The reaction product was GdOCl, which it was the unique solid phase produced in all the temperature range. The GdOCl is subsequently chlorinated producing GdCl3 for temperatures above 1123 K. The system is under chemical control at 723 K and it was found that the reaction order with respect to the chorine partial pressure is 0.77 and the activation energy is 132 kJ·mol-1. The global rate equation of was developed. The GdOCl obtained was characterized by X-ray diffraction, scanning electron microscopy and magnetic measurements. The structure of GdOCl was refined with the Rietveld method and it crystallized in a tetragonal form of REOX possessing the Matlockite-type (PbFCl) structure. The magnetic measurements indicated that the sample is paramagnetic at all the measurement range. The parameters of the Curie-Weiss law obtained were: θ = -12.0 K , C = 7.9592 emu∙K∙mol-1 and µeff = 7.98µB.