X-ray diffraction and Raman spectral analysis of molten CdCl2

Abstract

The structure of molten CdCl, has been investigated by X-ray diffraction and Raman spectral analysis. The tetrahedral configuration (CdCI,) was confirmed from the first and second peaks of the radial distribution function.

Local Structure of Molten CdCl2 Systems

“…Both results show that the local structure of molten CdCl 2 changes from the CaF 2 -type 6-fold to the 4-fold tetrahedral coordination (CdCl 4 ) 2− on melting. Although the result of molten CdCl 2 is close to the report by Takagi et al [5], the Cd 2+ -Cl − distance is significantly longer in the present work. The local structure around the Cd 2+ ion does not change by mixing with KCl, since XAFS data of the mixture were close to those of the pure melt.…”

“…The interionic distance of the pair Cd 2+ -Cl − decreases from 2.61Å to 2.47Å. The latter value is slightly larger than 2.42Å, reported by Takagi et al [5]. The decrease of the Cd 2+ -Cl − distance by 0.14Å on melting is close to the difference between the ionic radii Cd(6-fold) = 0.95Å and Cd(4-fold) = 0.78Å [15].…”

“…The sharp 1st peak at 2.50Å in the G(r) function is assigned to the nearest Cd 2+ -Cl − correlation. This value is larger than 2.42Å measured by Takagi et al [5], and is slightly shorter than the sum of the ionic radii [15] r[Cd (4-fold) and Cl] = 2.59Å. The coordination number, evaluated from the peak area with a cut-off distance r cut = 3.05Å is 4.1.…”

“…In the present study, the local structure of molten CdCl 2 and its mixtures with KCl was investigated by using high temperature XAFS. In addition, high temperature XRD measurements of molten CdCl 2 were performed to compare them with [5] and the present XAFS results.…”

“…Takagi et al [5] studied the structure of molten CdCl 2 by using X-ray diffraction (XRD) and Raman scattering methods. They concluded that the local structure of molten CdCl 2 is tetrahedral (CdCl 4 ) 2− .…”