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Raman spectroscopic studies of the various phases of crystalline ammonium fluosilicate (NH 4 ) 2 SiF 6
Author(s) -
Poulet H.,
Mathieu J. P.
Publication year - 1976
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250050210
Subject(s) - raman spectroscopy , trigonal crystal system , crystallography , symmetry (geometry) , phase (matter) , atmospheric temperature range , ammonium , phase transition , chemistry , spectral line , materials science , analytical chemistry (journal) , crystal structure , condensed matter physics , optics , thermodynamics , physics , geometry , mathematics , organic chemistry , astronomy , chromatography
Raman spectra of oriented single crystals of (NH 4 ) 2 SiF 6 are reported for the temperature range 440–20 K. The trigonal phase stable below 278 K undergoes a transition at 38.6 K. The changes in the spectra show that the symmetry does not remain trigonal, but give evidence for a lower symmetry.