Alluaudite-Like Structure of the Arsenate Na3In2(AsO4)3
1997; Elsevier BV; Volume: 134; Issue: 1 Linguagem: Inglês
10.1006/jssc.1997.7526
ISSN1095-726X
AutoresS. Khorari, A. Rulmont, P. Tarte,
Tópico(s)Chemical Synthesis and Characterization
ResumoThe arsenate Na3In2(AsO4)3has been synthesized and investigated by X-ray diffraction and vibrational spectroscopy. According to a Rietveld analysis, it is monoclinic, space group C2/c,Z=4, witha=12.6025 (1),b=13.1699 (1),c=6.8335 (1) Å,β=113.7422 (5). It has an alluaudite-like structure, with the three Na+cations located on the three large sites X(2), X(1), and M(1), and the two In3+cations on the M(2) sites of this structure. This is a new type of chemical formula (free from bivalent cations and with a full occupancy of the X(2), X(1), and M(1) sites by sodium ions) for an alluaudite-like structure. The Raman and infrared spectra exhibit a great number of sharp bands, as expected from the low symmetry and from the ordered distribution of the cations, but this complexity precludes a detailed assignment of the bands. Structural analogies or differences with other alluaudite-like compounds are briefly discussed.
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