Crystal structure of rare-earth silicon-oxynitride J-phases, Ln4Si2O7N2

Junichi Takahashi, Hisanori Yamane, Naoto Hirosaki, Yoshinobu Yamamoto, Mamoru Mitomo, Masahiko Shimada

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15 Citations (Scopus)


Rare-earth silicon-oxynitride J-phases, Ln4Si2 O7N2 (Ln=Y, La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), were prepared by the N2 gas-pressured sintering method at 1 MPa of N2 and 1500-1700 °C. The Rietveld analysis was carried out for X-ray powder diffraction data measured at room temperature. The crystal structures of Ln4 Si2O7N2 were refined with the structure model of La4Si2O7N2 for Ln=La, Pr, Nd, and Sm, and with that of Lu4Si2 O7N2 for Ln=Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. The refined monoclinic unit-cell parameters (lengths a, b, c, angles β, and volume V) increased linearly in their two series of Ln with increasing ionic radii of rare-earth atoms. Discontinuities of the unit-cell parameters were found between the two Ln series.

Original languageEnglish
Pages (from-to)793-799
Number of pages7
JournalJournal of the European Ceramic Society
Issue number6
Publication statusPublished - 2005 Mar


  • LnSiON
  • Powders-solid-state reaction
  • Rare-earth silicon-oxynitrides
  • X-ray methods


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