Europium. .. Radium

Experiments (Haire and Baybarz 1979) suggest that einsteinium has an fee structure, but with an atomic volume corresponding to a divalent ion configuration. This crystal structure should therefore be compared with those of europium (bcc) and ytterbium (fee). One can also discern a crystal structure sequence for divalent metals (Johansson and Rosengren 1974, 1975a), which may also be correlated with the d occupation number (Skriver 1982). When viewed in this light, einsteinium is more similar to ytterbium than to europium. Radium, on the other hand, has a bcc phase, which should be compared with barium (bcc) and europium (bcc). Slightly compressed radium is predicted to be a superconductor (Skriver 1982). 

Calcium, Ca strontium, Sr barium, Ba radium, Ra europium, Eu ytterbium, Yb... 

Eugene-Anatole Demarsay, 1852-1904. French chemist who discovered the element europium and gave spectroscopic proof of the discovery of radium by M and Mme. Curie. He investigated many terpcncs and ethers, and studied the volatility of metals at low temperatures and pressures... 

Twentieth Century Demargay discovers europium. Rutherford and Soddy discover thorium X. B. B. Boltwood, H. N. McCoy, and J. W. Strutt prove independently that radium is produced by spontaneous transmutation of uranium. 

Some substitution of strontium (up to 14 mol.%), of lead (2 mol.% reported) but no barium has been reported in aragonite, although investigations at elevated temperatures and pressures show almost complete miscibility of these elements in the structure (Gaines et al., 1997, p. 442), and SrCOs (strontionite), BaCOs (witherite), and PbCOs (cerussite) are common minerals. A calculated plot (Figure 3(b)) for cations in ninefold coordination shows that this coordination theoretically allows trivalent rare earth elements and quadravalent and many other elements to be substituents in the structure. Ytterbium, europium, samarium, and radium carbonates with aragonite structure have been synthesized (Spear, 1983). 

Activation analysis was first applied by von Hevesy and Levi two years after the discovery of artificial radioactivity (38). Determination of 0.1% dysprosium in rare earth mixtures was made by activation with neutrons from a 300-millicurie radium emanation-beryllium neutron source. The 2.3-hr half-life induced activity due to Dy was compared with that induced in mixtures of known dysprosium content. A similar method was used to determine europium in gadolinium. 

The third place is held by France where fifteen elements were discovered chromium (1797), beryllium (1798), boron (1808), iodine (1811), bromine (1826), gallium (1875), samarium (1879), gadolinium (1886), dysprosium (1886), radium (1898), polonium (1898), actinium (1899), europium (1901), lutecium (1907), francium (1939). It is not surprising that the radioactive elements polonium, radium, and actinium were discovered by French scientists. These discoveries proceeded from the pioneering studies of radioactivity conducted in France. A brilliant spectral analyst P. Lecoq de Boisbaudran discovered by means of spectral analysis four new elements—gallium and three rare-earth elements (samarium, gadolinium, and dysprosium). Chromium and beryllium were discovered by L. Vauquelin who was such a skillful analytical chemist that it would be unjust if he had not given the world at least one new element. 

In his career, before the discovery of europium in 1901, he had developed spectroscopy in order to make it more effective for the identification of RE metals. He used a special induction coU, which generated a very high spark temperature. The material of the electrodes was especially pure platinum. Thus all foreign spectral lines except those of platinum were eliminated. With this spectroscope Demarfay made a special contribution to science. Pierre Curie had brought to him a sample of barium, in which lines of radium could be observed for the first time (see Chapter 52 The Radioactive Elements). After the discovery of europium Demarfay had only a few years to live. He died in 1903. In ref. [17.19] James and Virginia Marshall have described the life of Demarfay and his discovery of europium. 

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