Ultrahigh-pressure polyamorphism in GeO2 glass with coordination number >6

Yoshio Kono, Curtis Kenney-Benson, Daijo Ikuta, Yuki Shibazaki, Yanbin Wang, Guoyin Shen, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


Knowledge of pressure-induced structural changes in glasses is important in various scientific fields as well as in engineering and industry. However, polyamorphism in glasses under high pressure remains poorly understood because of experimental challenges. Here we report new experimental findings of ultrahigh-pressure polyamorphism in GeO2 glass, investigated using a newly developed double-stage large-volume cell. The Ge-O coordination number (CN) is found to remain constant at ∼6 between 22.6 and 37.9 GPa. At higher pressures, CN begins to increase rapidly and reaches 7.4 at 91.7 GPa. This transformation begins when the oxygen-packing fraction in GeO2 glass is close to the maximal dense-packing state (the Kepler conjecture = ∼0.74), which provides new insights into structural changes in network-forming glasses and liquids with CN higher than 6 at ultrahigh-pressure conditions.

Original languageEnglish (US)
Pages (from-to)3436-3441
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number13
StatePublished - Mar 29 2016
Externally publishedYes


  • Glass
  • High pressure
  • Oxygen packing
  • Polyamorphism

ASJC Scopus subject areas

  • General


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