QUANTITATIVE-DETERMINATION OF F O RATIOS IN RARE-EARTH-OXIDE FLUORIDES BY ENERGY-DISPERSIVE X-RAY-ANALYSIS/

The F:O ratio in homogeneous and inhomogeneous rare earth oxide fluori de systems of compositions RO(1+x)F(1-2x) with -0.1 less than or equal to X less than or equal to 0.1 can be determined by energy dispersive X-ray (EDX) analysis with an accuracy of +/-0.5% if an appropriate ba ckground modelling procedure is applied and if the EDX signals of the light elements are free of overlap from the accompanying rare earth el ement. The latter condition holds true for R=Tb-Lu and it is shown tha t the calibration of the method with well-defined samples of YbO1+xF1- 2x can be transferred with only a moderate loss of accuracy to the det ermination of oxygen and fluorine in DyOF and ErOF. Increasing signal overlap in case of GdOF, EuOF, SmOF and especially PrOF necessitates t he choice of different channels for background modelling, and the accu racy of the method is hence decreasing to +/-4% for these systems.