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Microwave‐Assisted Hydrothermal Synthesis of Structurally and Morphologically Controlled Sodium Niobates by Using Niobic Acid as a Precursor
Author(s) -
Paula Amauri J.,
Zaghete Maria A.,
Longo Elson,
Varela José A.
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200701138
Subject(s) - chemistry , hydrothermal synthesis , hydrate , raman spectroscopy , hydrothermal circulation , ceramic , octahedron , phase (matter) , natural bond orbital , chemical engineering , mineralogy , inorganic chemistry , crystallography , nuclear chemistry , crystal structure , organic chemistry , molecule , physics , optics , engineering
There are many advantages to using a microwave as a source of heat in hydrothermal reactions. Because it is a quick and homogeneous way to crystallize ceramic powders, it was used in this work for the production of antiferroelectric sodium niobate (NaNbO 3 ) in a cubic‐like form and its intermediary phase, disodium diniobate hydrate (Na 2 Nb 2 O 6 .H 2 O), with a fiber morphology. The syntheses were carried out by treating niobic acid (Nb 2 O 5 · n H 2 O) with NaOH. By changing the reaction time and the concentration of the reactants, particles with different structures and different morphologies could be obtained. The structural evolution of the products of this reaction was elucidated on the basis of the arrangement of the NbO 6 octahedral units. Conclusive results were obtained with morphological and structural characterizations through XRD, TEM, MEV, and NMR and Raman spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)