Room-temperature sol-gel synthesis of sodium hexaniobate in an immiscible hexane-water system and its conversion into NaNbO 3

Masahiro Tanaka, Shinobu Fujihara

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6 Citations (Scopus)


Sodium hexaniobate (Na 7[HNb 6O 19] ·15H 2O) was synthesized by a one-pot sol-gel method at room temperature by using an immiscible, biphasic solution. An organic solution was prepared by dissolving niobium pentaethoxide [Nb(OC 2H 5) 5] in ethanol, which was then added to hexane. This solution was brought into contact with an aqueous NaOH solution to form a reaction system consisting of two separate phases. A white precipitate was formed within 12 h at the bottom of the aqueous solution. It exhibited well-defined rod-like morphology on a micrometer scale. A comparative study was performed on the basis of a single-phase solution by mixing Nb(OC 2H 5) 5 in ethanol and the aqueous NaOH solution. The results indicated that the product formed by way of the single-phase solution was rather different in morphology from that obtained in the biphasic system. In both cases, Na 7[HNb 6O 19] ·15H 2O could be converted to NaNbO 3 by heating at 600 °C. Mechanisms underlying the formation of Na 7[HNb 6O 19]·15H 2O and its conversion to NaNbO 3 are discussed on the basis of the experimental results.

Original languageEnglish
Pages (from-to)1180-1185
Number of pages6
JournalEuropean Journal of Inorganic Chemistry
Issue number8
Publication statusPublished - 2012 Mar 1



  • Alkoxides
  • Crystal growth
  • Niobium
  • Sol-gel processes

ASJC Scopus subject areas

  • Inorganic Chemistry

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