Gadolinium oxide is a rare earth, occurring between yttrium and samarium. It was discovered in 1880 by Marignac, and was at first called by him Y
α
, a designation which he soon changed for gadolinium. Since Marignac’s time much work has been done on this earth by Lecoq de Boisbaudran, Bettendorf, Cleve, Benedicks, Marc, Demarcay, Exner and Haschek, Urbain, and others. In the spring of this year, M. G. Urbain gave me some gadolinia and other rare earths, which he had prepared in a state of considerable purity by means of a novel system of fractionation in which use is made of the crystallisation of double nitrates of bismuth and magnesium with the rare earth nitrates. He finds that bismuth places itself between the ceric and the terbic groups, thus sharply separating samarium, the last member of the ceric group, from europium and gadolinium, the first members of the terbic groups. I have for some time past been fractionating rare earths by Urbain’s method, and can quite corroborate what he says.
SOLVENT EXTRACTION STUDY OF THE SYSTEM MONAZITE RARE EARTH NITRATES-NITRIC ACID-WATER-TRIBUTYL PHOSPHATE
