Sternlicht et al. analyzed Yb M 4,5 -, Si K-, O K-edges of Yb 2 Si 2 O 7 and Yb 2 SiO 5 for the quantitative estimation of atomic ratios. However, no detailed comparison of spectral shapes between the two compounds was presented. Among these spectra, in this study, we address the O K-edges that sensitively respond to coordination environments . Theoretical calculations of core-loss spectra based on the density functional theory (DFT; e.g., in combination with a core-hole technique), provide spectra comparable to experimental ones, as well as the interpretation of different spectral shapes and peak top positions .