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The Phase Transformation in Ferreous Fluosilicate Hexahydrate
Author(s) -
Spiering H.,
Vogel H.,
Irler W.
Publication year - 1977
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220820126
Subject(s) - anisotropy , materials science , phase (matter) , mössbauer spectroscopy , relaxation (psychology) , crystallography , phase transition , ion , analytical chemistry (journal) , condensed matter physics , chemistry , physics , optics , social psychology , chromatography , psychology , organic chemistry
The structural change of FeSiF 6 , . 6 H 2 O at T , = 225 K (P2 1 /C to P3ml above T e ) is well known from X‐ray measurements. The temperature dependence of the Mössbauer parameters in the neighbourhood of the phase transformation (200 K ≦ T ≦ 250 K) is studied. At T e , the quadru‐pole splitting Δ E q changes with increasing temperature by (+0.009 ± 0.002) mm/s, the Lamb factor f slightly decreases by δ f = −0.011 ±0.004, while the anisotropy of f changes remarkably: δ( f ∥ ‐ f⊥) = −0.18. From the relaxation broadening of the absorption lines below and above T e , it is concluded that the non‐axial terms of the ligand field at the Fe 2+ ion do not vanish above the transition temperature.