Absorption profiles of SiO isotopologues are overlaid by the best fit Gaussian components (black dotted line) and the sum of best-fit Gaussians (black solid line). Black vertical lines indicate the velocities of line absorption by Sgr B2 at +64 and +82  km s^-1, and colored lines are located at −106, −73.5, −40, and +3  km s^-1. The profile of ³⁰SiO includes a single detected component at −106  km s^-1 due to blending with the line-of-sight absorption profile of NH₂CHO.