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Temperature-dependent Raman scattering studies of Na2MoO4

✍ Scribed by G. D. Saraiva; W. Paraguassu; M. Maczka; P. T. C. Freire; J. A. Lima Jr.; C. W. A. Paschoal; J. Mendes Filho; A. G. Souza Filho

Publisher
John Wiley and Sons
Year
2008
Tongue
English
Weight
465 KB
Volume
39
Category
Article
ISSN
0377-0486

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✦ Synopsis

Abstract

The mode assignment of the cubic phase of anhydrous Na~2~MoO~4~ was carried out on the basis of lattice dynamic calculation using the classical rigid‐ion model. Temperature‐dependent studies indicate that this crystal remains in the cubic structure in the 15–773 K range and undergoes a phase transition at around 783 K. The behavior of the Raman modes indicates that this transition is strongly first‐order in nature and the phase above 773 K may have an orthorhombic symmetry. This transition is connected with tilting and/or rotations of the MoO~4~ tetrahedra, which lead to a disorder at the MoO~4~ sites. Our results give also evidence that the MoO bond lengths decrease in the high‐temperature phase. Copyright © 2008 John Wiley & Sons, Ltd.

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