Dias, AndersonSiqueira, Kisla Prislen FélixMoreira, Roberto Luiz2017-05-182017-05-182010DIAS, A.; SIQUEIRA, K. P. F.; MOREIRA, R. L. Crystal structures and phonon modes of Ba(Ca1/2W1/2)O3, Ba(Ca1/2Mo1/2)O3 and Ba(Sr1/2W1/2)O3 complex perovskites investigated by Raman scattering. Journal of Raman Spectroscopy, v. 41, p. 93-97, 2010. Disponível em: <http://onlinelibrary.wiley.com/doi/10.1002/jrs.2399/abstract>. Acesso em: 20 abr. 2017.1097-4555http://www.repositorio.ufop.br/handle/123456789/7763This work investigates the crystal structures and phonon modes of Ba(Ca1/2W1/2)O3, Ba(Ca1/2Mo1/2)O3 and Ba(Sr1/2W1/2)O3 perovskites by Raman spectroscopy. The samples were produced by conventional solid-state processing at 1200 ◦C. X-ray diffraction showed that single-phase homogeneous materials were produced, which are cubic or pseudo-cubic in symmetry. The existing controversies in the literature for these complex perovskiteswere investigated by comparing experimental Raman data with group-theory analysis. Ceramicswith Ca andWorMowere found to be cubic, space group Fm3m. For thesematerials, four Raman-active bands were observed and the fitting parameters showed that the Ba(Ca1/2Mo1/2)O3 ceramic presents bands at lower wavenumbers if compared with the Ba(Ca1/2W1/2)O3 sample. For the Ba(Sr1/2W1/2)O3 material, two hypotheses were investigated for monoclinic or triclinic structures. The experimental results showed 12 Raman-active modes for this ceramic, which is in perfect agreement with the theoretical predictions for a monoclinic (I2/m) structure.en-USrestritoDouble perovskitesRaman spectroscopyCeramicsMicrowave dielectricsArtigo publicado em periodicohttp://onlinelibrary.wiley.com/doi/10.1002/jrs.2399/abstracthttps://doi.org/10.1002/jrs.2399