Junaid, Bushiri M; Antony, C J; Aatiq, A; Yohannan Panicker, C; Hema, Tresa Varghese; Manojkumar, T K(Elsevier, November 15, 2010)
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Abstract:
FT-Raman and FT-IR spectra of ASnFe(PO4)3 [A=Na2, Ca, Cd] were recorded and analyzed. The bands
were assigned in terms of the vibrational group frequencies of SnO6 octahedral and PO4 tetrahedral. The
spectral analysis shows that the symmetry of corner shared octahedral (SnO6) and the tetrahedral (PO4)
are lowered from their free ion symmetry state. The presence of Fe3+ ions disrupts the S–N–O–S–N chain
in the structure. This causes distortion of SnO6 and PO4 in the structure of all the compounds. Also it is
seen that there are two distinct PO4 tetrahedra of different P–O bond lengths. One of these tetrahedra
is linearly distorted in all the title compounds. The PO4 frequencies and bond lengths are calculated
theoretically and are in agreement with the experimental values. The presence of PO4 polyanion in the
structure can reduce the redox energy and hence reduce the metal oxygen covalency strength in the
structure