Journal of East China Normal University(Natural Sc ›› 2008, Vol. 2008 ›› Issue (4): 78-87.

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Thermal decomposition behavior of metal-oxygen clusters with Dawson structure(English)

KONG Ai-guo, LI Jiang, LAI Ke-qiang, ZHANG Gui-rong, DING Han-ming, SHAN Yong-kui   

  1. Department of Chemistry, East China Normal University, Shanghai200062, China
  • Received:2007-04-01 Revised:2007-06-05 Online:2008-07-25 Published:2008-07-25
  • Contact: SHAN Yong-kui

Abstract: The thermal decomposition behavior of metal-oxygen clusters with Dawson structure, YmHnP2M18O62•qH2O, was systematically investigated using the X-ray power thermodiffractometry and FTIR at different temperatures, TG-DTA. The experimental results indicated that Dawson-type metal-oxygen clusters with anion,[P2Mo18O62]6-,and different counter cations,NH4+,Cu2+,K+,underwent an irreversible thermal rearrangement around 210 ℃,240 ℃,250 ℃, respectively to give the corresponding Keggin-type metal-oxygen clusters containing [PMo12O40]3-as one of the products. For the metal-oxygen clusters containing tungsten, the pyrolysis procedure of potassium salt with [P2W18O62]6-anion is similar to that of metal-oxygen clusters with [P2Mo18O62]6-anion, whenas the NH4+, Cu2+salts of [P2W18O62]6-seem to decompose directly into WO3 at 400 ℃, 450 ℃,respectively.These results testify that the thermal solid-state rearrangements of Dawson-type anions correlated with the thermal stability of the corresponding Keggin-type compounds. Furthermore, some proposals about the criterion and the adjudication of thermal decomposition temperature for metal-oxygen clusters with different thermal decomposition behavior are also given.

Key words: metal-oxygen clusters, thermal decomposition, Dawson structure, metal-oxygen clusters, thermal decomposition

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