Purity Level of Rare-Earth Metals (according to Materials in the Exhibition–Collection of Extrapure Substances)

— In this paper, we examine the purity level and impurity composition of rare-earth metals represented at the Exhibition–Collection of Extrapure Substances and present estimates of the average and total concentrations of elemental impurities in the purest samples. We analyze the impurity composition of the entire array of rare-earth metals and contributions of particular groups of impurities.