Infrarotspektren der Hexachalkogenohypodiphosphat-Mischkristalle Ni₂P₂S₆-xSe_x und Co₂-xNi_xS₆ / Infrared spectra of the hexachalcogenohypodiphosphate mixed crystals Co_2-xNi_xP₂S₆ and Ni₂P₂S_6-xSe_x

Abstract

Abstract The hexachalcogenohypodiphosphate mixed crystals Co 2-x Ni x P 2 S 6 and Ni 2 P 2 S 6-x Set have been prepared and characterized by x-ray powder methods and infrared spectroscopy. The spectra of the anionic substituted mixed crystals show the existence of mixed anionic species like e.g. P 2 S 5 Se or P 2 S 4 Se 2 . Cationic substitution leads to a one mode behaviour of the internal modes of the P 2 S 6 -units with different frequency shifts for the E u and A 2u modes and a two mode behaviour of the external modes. Attempts to prepare mixed crystals Co 2 P 2 S 6-x Se x failed; only small amounts of selenium can be detected in Co 2 P 2 S 6 .