Temperature‐dependent vibrational studies of [N(C2H5)4]2MnCl4

Abstract Room‐temperature polarized Raman spectra of a single crystal and IR spectra of a polycrystalline sample were measured for [N(C 2 H 5 ) 4 ] 2 MnCl 4 and the assignment of the observed bands to the respective modes has been proposed. Temperature‐dependent Raman and far‐IR studies were also performed for the polycrystalline sample in order to obtain information on changes occurring in this material as a result of phase transitions at T 1 = 227 K and at T 2 = 199 K. These studies revealed that the higher‐temperature ferroelastic phase transition is associated with significant modification of vibrational properties due to ordering of tetraethylammonium groups. The lower‐temperature phase transition does not lead to any clear changes in the spectra. However, our results suggest that disorder of MnCl 4 2− ions decreases with decreasing temperature. Copyright © 2007 John Wiley & Sons, Ltd.