Velocity-integrated intensity maps of HCO⁺ (6km s⁻¹ to 15.6km s⁻¹), N₂H⁺ (−1.2km s⁻¹ to 17.2km s⁻¹ spanning all the hfs transitions) in the upper row and SiO (8km s⁻¹ to 10km s⁻¹) and NH₂D (0km s⁻¹ to 15.2km s⁻¹ covering all the hfs transitions) in the lower row. The black contours represent the GBT+NOEMA combined 3.6 mm continuum emission, and the bright green marker indicates the position of the ionizing source, DR18-05. The contour levels of the mm continuum are the same as shown in Fig. 3. The horizontal white scale bar has a size of 0.1 pc at a given distance of 1.4 kpc. The beam of the maps of each species is displayed on the left corner of each image panel.