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Journal of Materials Science

, Volume 26, Issue 15, pp 4179–4185 | Cite as

The thermal property of alkaline earth diphosphates made by a wet process

  • Makoto Watanabe
  • Shinsaku Furuta
  • Shigeru Onoda
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  • 28 Downloads

Abstract

Alkaline earth diphosphates [K2Mg3(P2O7)2·6H20, 2Mg2P2O7·15H2O, Sr2P2O7·3H2O, and Ba2P2O7·2H2O] were made by mixing solutions of tetrapotassium diphosphate and alkaline earth dichlorides. These diphosphates showed the following thermal reactions when they were heated up to 1000 °C:
  1. 1.

    dehydration M4P2O7·nH2O → M4P2O7·(n−x)H2O + xH2O (0<x⩽n)

     
  2. 2.

    degradation M4P2O7 + H2O → 2M2HPO4

     
  3. 3.

    disproportionation or metathesis 2M2HPO4 → M3PO4 + MH2PO4

     
  4. 4.

    polymerization 2M2HPO4 + nMH2PO4 → Mn+4Pn+2O3n+7 + (n+1)H2O

     
  5. 5.

    reorganization or degradation to diphosphate Mn+2PnO3n+1 + (n−2)M3PO4 → (n−1)M4P2O7

     
  6. 6.

    reorganization or degradation to tri- and/or diphosphates (for only Ba2P2O7·2H2O) Mn+2PnO3n+1 + 1/2 (n−3)M3PO4 → 1/2 (n−1)M5P3O10 (n⩾3) Mn+2PnO3n+1 + (n−3)M3PO4 → M5P3O10 + (2n−4)M4P2O7 (n⩾3) where M stands for K and/or 1/2Mg, 1/2Sr, or 1/2Ba.

     

Keywords

Polymer 2H2O Dehydration Thermal Property Diphosphate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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Copyright information

© Chapman and Hall Ltd 1991

Authors and Affiliations

  • Makoto Watanabe
    • 1
  • Shinsaku Furuta
    • 1
  • Shigeru Onoda
    • 1
  1. 1.Department of Industrial ChemistryChubu UniversityAichiJapan

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