Comparison between the JWST/MIRI spectrum of B1-c (gray) and the lab spectra (colors) in the COM fingerprint range of 6.8–8.8 μm. Each panel focuses on one species and shows the comparison between the observed B1-c spectrum and the lab spectra with different mixing constituents, except for panel c, which shows the lab spectra of HCOO⁻ under different temperatures. The observed spectrum along with the 3σ level is shown in light gray, except for panel a, which blows up the CH₄ band at ~7.7 μm, and the observed spectrum is plotted in black for clarity. In each panel, the spectrum in blue corresponds to the pure ice, and the best-fit spectrum to the observations is highlighted with a thicker red line. A similar comparison but for lab spectra under different temperatures is shown in Figs. 5 and C.1.