Debieme, Andre

Radium - the atomic number is 88 and the chemical symbol is Ra. The name derives from the Latin radius for beam or ray because of its tremendous ray-emitting power. It was discovered by the French physicist Pierre Curie and the Polish-bom, French chemist Marie Sklodowska Curie in 1898. It was independently discovered by the British chemists Frederick Soddy and John A. Cranston. It was first isolated in 1910 by Marie Curie and the French chemist Andre-Louis Debieme. The longest half-life associated with this unstable element is 1599 year Ra. 

The second member of the series is radium itself. The task of isolating it was most difficult, and involved risk of losing the precious product. In 1910, however, Mme. Curie and M. Andre Debieme finally succeeded in preparing the shining white metal but, since they needed the radium in their researches, they did not keep it in this form. 

The name comes from the Latin radius, meaning ray. It was discovered by Marie and Pierre Curie in 1898 when they were studying uranium and other radioactive materials found in pitchblende. There is about 1 g of radium in 7 tons of pitchblende, but it is 3xl05 times more radioactive than uranium. It was isolated as a metallic element in 1911 by Marie Curie and Andre-Louis Debieme (1874-1949). Radium exists in small quantities associated with uranium ores. Radium is phosphorescent, so it has been used to make luminous paint, especially for watch dials, but, because it is highly radioactive, most uses are related to nuclear medicine or the energy industry. Radon gas is produced from radium and is a harmful by-product. 

Other strongly radioactive elements were discovered in tiny traces. In 1899, the French chemist Andre Louis Debieme (1874-1949) discovered actinium. In 1900, the German physicist Friedrich Ernst Dom (1848-1916) found a radioactive gas which eventually received the name radon. It was one of the inert gases (see page 143), fitting below xenon in the periodic table. Finally, in 1917, the German chemists Otto Hahn (1879- ) and Lise Meitner (1878- ) discovered protactinium. 

Radium was discovered by Marie Curie and her husband Pierre in 1898 while removing uranium from pitchblende. They noticed that the remaining material was still radioactive. It wasn t until 1910 when it was isolated as a pure metal Marie Curie and Andre-Louis Debieme achieved this by electrolysis. 

A third new radioactive element was discovered in the pitchblende residues by Andre Debieme (1874-1949), who was working with the Curies. It was precipitated with the rare-earth elements, but like polonium it was present in such minute quantity that neither the element nor any of its compounds could be isolated in a pure form. This element was named actinium. 

In their hunt for new elements, Marie and Pierre Curie treated a batch of material with strong hydrochloric acid. Both the solution and the insoluble residue were radioactive. From the hydrochloric add solution, sulfides were precipitated with hydrogen sulfide. The radioactivity followed bismuth. Andre Debieme introduced a modified technique. An iron foil was placed in the acid solution. Metals nobler than iron, thus copper, lead and bismuth, precipitated, at least partially. The radioactivity followed this metallic fraction. 

It was mentioned above that the two Curies had called upon Andre Debieme for chemical support in the separation of the pitchblende residues. In that connection he made his own element discovery in 1899. 

Actinium — (Gr. aktis, aktinos, beam or ray), Ac at. wt. (227) at. no. 89 m.p. 1051°C, b.p. 3200 300°C (est.) sp. gr. 10.07 (calc.). Discovered by Andre Debieme in 1899 and independently by E Giesel in 1902. Occurs naturally in association with uranium minerals. Thirty four isotopes and isomers are now recognized. All are radioactive. Actinium-227, a decay product of uranium-235, is an alpha and beta emitter with a 21.77-year half-life. Its principal decay products are thorium-227 (18.72-day half-life), radium-223 (11.4-day half-life), and a number of short-lived products including radon, bismuth, polonium, and lead isotopes. In equilibrium with its decay products, it is a powerful source of alpha rays. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300°C. The chemical behavior of actinium is similar to that of the rare earths, particularly lanthanum. Purified actinium comes into equilibrium with... 

---