The Krasnoyarsk scientist studied the interactions of perfluorinated diketones with rare earth metals and found several interesting patterns. Understanding these processes will allow for more efficient separation and production of rare earth metals. The results summarizing a series of research papers are published in the Journal of the American Chemical Society The Journal of Physical Chemistry A and selected as the cover illustration of the October issue of this publication.

Rare earth metals such as scandium, yttrium, europium are widely used in various industries, for example, in electronics, medicine, energy and the production of permanent magnets, catalysts for oil and gas refining, as well as in the production of special alloys for the aerospace industry. However, rare earth metals are difficult to separate among themselves. In solution, this can be done by using selective reagents. For example, such as perfluorinated diketones. Perfluorinated heterocyclic diketones are compounds containing fluorine atoms, as well as one of the chalcogen atoms – oxygen, sulfur, selenium or tellurium. They can interact with rare earth metal ions and selectively separate them.

In a series of several papers, a scientist at the Krasnoyarsk Scientific Center of the SB RAS determined the parameters of interaction of perfluorinated diketones with rare earth metal ions, and the generalized results published in the article helped to understand the fundamental patterns. Understanding these processes will help to extract rare earth metals more efficiently from their scattered deposits.

The specialist collected a large amount of data and determined more than 150 stability constants – measures of the energy of interaction between metal ions and diketones. Knowledge of stability constants is important for determining the conditions of chemical reactions and choosing optimal conditions for the separation of rare earth metals. The chemist considered how the various atoms that make up the diketones affect these properties, as well as the location of these atoms relative to each other. The study of substituted groups found that in the case of diketons, "anti-Coulomb" behavior is manifested. According to the electrostatic interaction model, diketones with heavier chalcogen atoms should form weaker complexes with metals, and the experiment shows the opposite. Thus, the correlations found are inversely opposite to what the electrostatic model of metal-ion interaction predicts. The correlation between the metals themselves within a single diketone, on the contrary, demonstrates a strict Coulomb correlation.

"In a series of papers preceding this article, a large array of spectral and thermodynamic data on the interaction of rare earth elements with diketones was obtained. However, the lack of data on the interaction of metals with the background ions of the buffer greatly hindered obtaining accurate values. In this article, all available data were summarized to assess this effect and exact correlations of stability constants with periodic parameters were obtained. Accurate determination of stability constants will not only allow us to obtain useful data for selective separation of metals, but also to better understand the nature of the binding of metals with diketones," Maxim Lutoshkin, Candidate of Chemical Sciences, researcher at the Laboratory of Molecular Spectroscopy and Analysis of the Institute of Chemistry and Chemical Technology of the FITC KNC SB RAS.

PHOTO: Solutions of rare earth metals neodymium and praseodymium and platinum solution. Photo by Anastasia Tamarovskaya / FITC KNC SB RAS

Information and photos provided by the Federal Research Center "Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences"

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