Solikamsk Magnesium Plant OJSC, Solikamsk, Russia

P. G. Detkov, Member of the Board, Candidate of Technical Sciences, e-mail: p.detkov@yandex.ru

Independent Expert, Moscow, Russia
D. V. Drobot, Doctor of Chemical Sciences, e-mail: dvdrobot@mail.ru

In 1879, Paul-Émile Lecoq de Boisbaudran, the French chemist, published his research on materials isolated from the samarskite mineral. When conducting a spectroscopic examination of the samples, the scientist observed spectral lines that had not been previously found in any of the known descriptions of spectra. The resulting material was characterized by two strong lines with wavelengths of 480 and 463.5 nm in the blue region of the spectrum. According to the scientist’s opinion, these facts clearly supported the existence of a new element. He named it as ‘samarium’ after the mineral, where this element was discovered. In 1880, the results of his research on the North American samarskite, which took about two years, were published by Jean Charles Galissard de Marignac, the Swiss scientist. To separate the components in the fraction with a high content of yttrium and didymium, the scientist used the fractional precipitation of double sulfates in a saturated solution of potassium sulfate and determined their solubility. Marignac used the measurement of the equivalent mass of separation products as an additional control method. He was sure that he had discovered an oxide of a previously unknown element, as its mass equivalent was the highest among the oxides neighboring it in solubility. The scientist considered that he had no right to give this new element a name until he was sure that salts of the ele ment were of purity sufficient to carry out a study on their properties. Marignac gave this element a temporary designation of ‘Yα’. A few years later, the scientist chose the name ‘gadolinium’. Subsequent study on the properties of samarium and gadolinium led the scientists, such as William Crookes and Lecoq de Boisbaudran, to making an assumption about the existence of an unknown element similar in properties to these metals. In 1897, Eugène-Anatole Demarçay, the French chemist, confirmed in his research paper the assumptions made earlier in research by Crookes and Boisbaudran about the existence of a new element. Using the method of a fractional separation of double magnesium nitrates, the scientist, having carried out meticulous work, accumulated a sufficient number of compounds of the new element, contributing to conducting detailed spectroscopic studies and confirming the existence of the rare earth element. Demarçay suggested the name of the new element, ‘europium’. Then the existence of europium was confirmed by the French scientists, Georges Urbain and Henry Lacombe, who published their research on the separation of europium from samarium and gadolinium in 1903–1904. They modified the method of fractional crystallization of double magnesium nitrates and rare earth elements developed by Demarçay by adding double magnesium nitrates and rare earth elements with a large amount of double magnesium nitrate and bismuth to the solution, which contributed to the efficient separation of the samarium compound into head fractions and gadolinium into end fractions. According to data of these researchers, the atomic mass of europium was 151.79.

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