TABLE 3.

Analytical results of impurities in the original La₂O₃ sample.

Element	Measured mass fraction (mg kg−1)	Relative standard uncertainty due to standard solution (%)	Relative standard uncertainty due to calibration (%)	Relative standard uncertainty due to measurement repeatability (%)	Combined standard uncertainty (mg kg−1)
Sc	<0.2				0.057
Y	0.20	0.05	2.3	1.9	0.0059
Ce	0.09	0.11	2.6	2.8	0.0035
Pr	0.048	0.11	2.0	1.6	0.0012
Nd	0.13	0.12	2.5	2.1	0.0043
Sm	<0.011				0.0032
Eu	<0.002				0.00057
Gd	<0.010				0.0029
Tb	0.0032	0.14	5.9	2.4	0.0002
Dy	0.017	0.11	6.9	4.9	0.0014
Ho	0.018	0.11	2.2	2.6	0.0006
Er	0.033	0.12	2.6	4.5	0.0017
Tm	0.01	0.18	1.9	4.6	0.0019
Yb	<0.62				0.18
Lu	0.0039	0.14	4.4	4.2	0.0002
Th	<0.0022				0.001
Total amounts of impurities	1.0				0.19