Raman evidence for the congruently melting compound KLi(NO3)2 in the LiNO3-KNO3 system

Raman spectroscopy was employed to investigate the eutectic system of LiNO3-KNO3. A new metastable compound was identified by comparison between the spectra of the quenched and naturally cooled samples. The existence of the new compound suggested that LiNO3-KNO3 is a simple syntectic system with a congruently melting compound KLi(NO3)(2) instead of a eutectic system. Analysis of the Raman spectrum indicated that KLi(NO3)(2) has a crystal structure with nitrate ions on two distinct crystallographic sites similar to that found in the structure of KAg(NO3)(2). These studies emphasized the value of Raman spectroscopy as a complementary tool to DSC and XRD for phase Equilibrium studies. (C) 1998 Elsevier Science Ltd. All rights reserved.