The polycrystalline single-phase sample of La4Si2O7N2 was prepared at 1773 and 1873 K by the gas-pressured sintering method. The structure refinement was carried out by the Rietveld method using time-of-flight neutron powder diffraction data measured at 297 K. La4Si2O7N2 is isostructural with the Y4Al2O9 high-temperature phase and crystallizes in a monoclinic cell, P21/c (No. 14-1), Z = 4. The lattice parameters refined for the sample prepared at 1773 K were α = 8.0375(2) Å, b = 10.9900(2) Å, c = 11.1115(2) Å, and β = 110.9214(14)°. Nitrogen atoms statistically occupy the bridging site and the terminal sites of Si2O5N2 ditetrahedra in the La4Si2O7N2 structure. The nonmetal sites surrounded by La atoms only are fully occupied by oxygen atoms.
|Number of pages||6|
|Journal||Chemistry of Materials|
|Publication status||Published - 2003 Mar 11|
ASJC Scopus subject areas
- Chemical Engineering(all)
- Materials Chemistry