Chapter 10 - Direct Methods of Investigation

Abstract

This chapter discusses the proposed direct methods of investigation for the study of molten salt structures. The major direct methods used are X-ray and neutron diffraction analyses, infrared and Raman spectroscopy, NMR (nuclear magnetic resonance) measurement, and XAFS (X-ray Absorption Fine Structure) measurement in melts, are developed. However, the most frequently used direct methods discussed are X-ray and XAFS measurements, Raman spectroscopy, and NMR measurements. X-ray diffraction and XAFS measurements are powerful techniques to investigate the local atomic structure of solid and liquid phases and are successfully applied to many types of materials, such as solutions, catalysts, and amorphous solids. However, they encounter common difficulties due to high temperature, cost, and their specific properties in the experimental work. The results of Raman spectroscopy are reported for a number of inorganic melts as it provides specific information on the structure of molecules, on the chemical environment of atoms and their oxidation state. NMR examines directly the properties and behavior of a specific element. The chapter also explains Raman spectroscopy as it has proved to be a very useful tool in the study of molten salts structure.