Although they estimated the generated phase to be Y 2 Si 2 O 7 from a comparison with the experimental O K-edge via STEM-EELS, the validity is uncertain because the small difference in the simulated two spectra. Ching et al. reported various core-loss spectra, including O K-edges for compounds in the Y-Si-O-N system. However, a comparison with experimental data for Y 2 Si 2 O 7 and Y 2 SiO 5 was not shown. To our knowledge, O K-edge spectra of rare-earth silicates (i.e., R 2 Si 2 O 7 or R 2 SiO 5 ) have yet to be clearly characterized, and their applicability for structure identification is obscure.