Hydrothermal synthesis of perovskite and pyrochlore powders of potassium tantalate

Gregory K L Goh, Sossina M. Haile, Carlos G. Levi, Fred F. Lange

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73 Scopus citations


Potassium tantalate powders were hydrothermally synthesized at 100 to 200°C in 4 to 15 M aqueous KOH solutions. A defect pyrochlore, KTa2O5(OH) · nH2O (n ≈ 1.4), was obtained at 4 M KOH, but at 7-12 M KOH, this pyrochlore was gradually replaced by a defect perovskite as the stable phase. At 15 M KOH, there was no intermediate pyrochlore, only a defect perovskite, K0.85Ta0.92O2.43(OH)0.57 · 0.15H2O. Synthesis at higher KOH concentrations led to greater incorporation of protons in the perovskite structures. The potassium vacancies required for charge compensation of incorporated protons could accommodate water molecules in the perovskite structure.

Original languageEnglish (US)
Pages (from-to)3168-3176
Number of pages9
JournalJournal of Materials Research
Issue number12
StatePublished - Dec 2002

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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