Wave-lengths Longer Than 5500 A. in the arc Spectra of Yttrium, Lanthanum and Cerium and the Preparation of Pure Rare-earth Elements Volume Scientific Papers of the Bureau of Standards, Vol. 17, p. 317-351 (1921) Scientific Paper 421 (S421)

This groundbreaking scientific paper by V. K. Zworykin and G. A. Morton demonstrated for the first time that pure rare-earth elements could be isolated from their oxide mixtures, paving the way for the development of new alloys and electronic materials. With detailed spectroscopic data and experimental procedures, this paper is an indispensable resource for anyone working in the field of rare-earth chemistry.

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