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Chemical properties of some elements in a molten lithium chloride, potassium chloride eutectic (1962); Proprietes chimiques de quelques elements dans l'eutectique chlorure de lithium-chlorure de potassium fondu (1962)

Abstract

The increasing use of molten media especially in chemical preparations and for certain technological applications, has made it more necessary to have a knowledge of the chemical properties of elements in these solvents. Structural studies on molten solutions show the existence of certain species such as ions and complexes known to exist in aqueous solutions. This fact, together with certain experiments on chemical reactions in molten media has led us to establish a comparison between these media and aqueous solutions. We wish to show that the same fundamental phenomena occur in these media as are found in the chemistry of aqueous solutions and that this makes it possible to predict certain reactions. We have taken as examples the chemical properties of vanadium, uranium and sulphur in a LiCl-KCl eutectic melted at 480 deg. C. The first problem is to identify the various degrees of oxidation of these elements existing in the solvent chosen. We have tried to resolve it by comparing the absorption spectra obtained in aqueous solution and in the molten eutectic. We consider the possibilities of this method in a chapter on absorption spectrophotometry in the LiCl-KCl eutectic. During the study of the chemical properties we stress the  More>>
Authors:
Molina, R [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Dec 15, 1961
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-2125
Resource Relation:
Other Information: TH: These sciences; 60 refs
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; AQUEOUS SOLUTIONS; CHEMICAL PROPERTIES; COMPARATIVE EVALUATIONS; EUTECTICS; MOLTEN SALTS; OXYGEN COMPLEXES; REDOX POTENTIAL; REDOX REACTIONS; VALENCE
OSTI ID:
20740244
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France); Faculte des Sciences de l'Universite de Paris, 75 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR06R2125050060
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
76 pages
Announcement Date:
Jun 19, 2006

Citation Formats

Molina, R. Chemical properties of some elements in a molten lithium chloride, potassium chloride eutectic (1962); Proprietes chimiques de quelques elements dans l'eutectique chlorure de lithium-chlorure de potassium fondu (1962). France: N. p., 1961. Web.
Molina, R. Chemical properties of some elements in a molten lithium chloride, potassium chloride eutectic (1962); Proprietes chimiques de quelques elements dans l'eutectique chlorure de lithium-chlorure de potassium fondu (1962). France.
Molina, R. 1961. "Chemical properties of some elements in a molten lithium chloride, potassium chloride eutectic (1962); Proprietes chimiques de quelques elements dans l'eutectique chlorure de lithium-chlorure de potassium fondu (1962)." France.
@misc{etde_20740244,
title = {Chemical properties of some elements in a molten lithium chloride, potassium chloride eutectic (1962); Proprietes chimiques de quelques elements dans l'eutectique chlorure de lithium-chlorure de potassium fondu (1962)}
author = {Molina, R}
abstractNote = {The increasing use of molten media especially in chemical preparations and for certain technological applications, has made it more necessary to have a knowledge of the chemical properties of elements in these solvents. Structural studies on molten solutions show the existence of certain species such as ions and complexes known to exist in aqueous solutions. This fact, together with certain experiments on chemical reactions in molten media has led us to establish a comparison between these media and aqueous solutions. We wish to show that the same fundamental phenomena occur in these media as are found in the chemistry of aqueous solutions and that this makes it possible to predict certain reactions. We have taken as examples the chemical properties of vanadium, uranium and sulphur in a LiCl-KCl eutectic melted at 480 deg. C. The first problem is to identify the various degrees of oxidation of these elements existing in the solvent chosen. We have tried to resolve it by comparing the absorption spectra obtained in aqueous solution and in the molten eutectic. We consider the possibilities of this method in a chapter on absorption spectrophotometry in the LiCl-KCl eutectic. During the study of the chemical properties we stress the various methods of displacing the equilibria: complex formation, variation of the oxidation-reduction properties with complex formation. The complexes of the O{sup 2-} ion are considered in particular. The study of the exchange of this particle is facilitated by the use of a classification of some of its complexes which we call the pO{sup 2-} scale by analogy with the pH scale; the value pO{sup 2-} is defined by the relationship: pO{sup 2-} = log O{sup 2-} Similarly, the use of apparent potential diagrams pO{sup 2-} makes it possible to predict and to interpret reactions involving the simultaneous exchange of electrons and O{sup 2-} ions between the various degrees of oxidation of the same element. It is possible, by studying some reactions of this type between two elements. We give the diagrams of uranium and sulphur as examples. The chemical properties of sulphur show that the dismutation phenomenon operates also in molten media reactions, thus emphasising the resemblance with aqueous solutions. Finally, we show briefly how it is possible to predict qualitatively the chemical properties of a given element in a molten solvent other than the LiCl-KCl eutectic. (author) [French] Le developpement de l'utilisation des milieux fondus notamment en chimie preparative et pour certaines applications technologiques, a pose le probleme de la connaissance des proprietes chimiques des elements dans ces solvants. Les etudes de structure des solutions fondues font etat de l'existence d'especes connues en solution aqueuse, telles que les ions et les complexes. Ce fait et d'autre part quelques travaux portant sur l'etude de reactions chimiques en milieu fondu, nous ont amene a etablir une comparaison entre ces milieux et les solutions aqueuses. Nous nous sommes proposes de montrer que l'on retrouve dans ces milieux les phenomenes fondamentaux de la chimie des solutions aqueuses, permettant de prevoir et d'interpreter les reactions. Les proprietes chimiques du vanadium, de l'uranium et du soufre dans l'eutectique LiCl-KCl fondu a 480 deg. C, nous ont servi d'exemple. Le premier probleme est l'identification des divers degres d'oxydation de ces elements existant dans le solvant choisi. Nous avons tente de le resoudre par la comparaison des spectres d'absorption obtenus en solution aqueuse et dans l'eutectique fondu. Nous discutons les possibilites de cette methode dans un chapitre consacre a la spectrophotometrie d'absorption dans l'eutectique LiCl-KCl. Au cours de l'etude des proprietes chimiques, nous insistons sur les moyens mis en oeuvre pour deplacer les equilibres: formation de complexes, variation des proprietes oxydo-reductrices avec la formation de complexes L'attention est plus particulierement portee sur les complexes de l'ion O{sup 2-}. L'etude de l'echange de cette particule est facilitee par l'etablissement d'une classification de quelques-uns de ses complexes, que par analogie avec l'echelle de pH nous appelons 'echelle de pO{sup 2-}'; la grandeur pO{sup 2-} etant definie par la relation: pO{sup 2-} = - log O{sup 2-} Dans le meme ordre d'idees, l'utilisation de diagrammes potentiel apparent pO{sup 2-} - rend possibles la prevision et l'interpretation des reactions mettant en jeu l'echange simultane d'electrons et d'ions O{sup 2-} entre les differents degres d'oxydation d'un meme element. L'etude de quelques reactions de ce type entre deux elements distincts permet de placer, l'un par rapport a l'autre, les diagrammes relatifs a chacun de ces elements. Nous en fournissons un exemple a propos des diagrammes de l'uranium et du soufre. Les proprietes chimiques du soufre montrent que le phenomene de dismutation entre egalement dans les reactions observees en milieu fondu, accentuant ainsi tes analogies avec les solutions aqueuses. Pour terminer, nous montrons brievement comment il est possible de prevoir qualitativement les proprietes chimiques d'un element donne dans un solvant fondu. autre que l'eutectique LiCl-KCl. (auteur)}
place = {France}
year = {1961}
month = {Dec}
}