A New Product of Actinium

Abstract

RECENT work has directed attention to the great similarity in the modes of transformation of actinium and thorium. Thorium, probably itself inactive, gives rise to radio-thorium (Hahn, Jahrbuch d. Radioact. u. Eleklron., ii., 3330) which emits a rays; radio-thorium forms thorium X, which is followed by the other well known products, the emanation and the active deposit. Actinium behaves in a very similar way. By the same method, which was successful in separating thorium X from thorium, Gndlewski (Phil. Mag., July, 1905) showed that a new product, actinium X, could be separated from actinium. Actinium X produces the emanation, and this in turn the active deposit. The similarity between these two substances is even closer, for I have found that a new product is present in actinium which is intermediate between actinium and actinium X, and, from analogy to thorium, will be called for convenience “radio-actinium.” This product emits rays, is half-transformed in about twenty days, and is the parent of actinium X.