Comparison of the column densities of CN, HCN, and HNC, i.e., the cyanogen- or CN-bearing molecular family. The black symbols correspond to the absorption study against Galactic star-forming regions by Godard et al. (2010), the blue symbols correspond to the absorption study against quasars by Lucas & Liszt (2000a), yellow points refer to the absorption line study of a z = 0.89 galaxy by Muller et al. (2011), and the red symbols correspond to this work. The red points with highest column density correspond to the gas in the Galactic disk (v ~ 0 km s⁻¹), and the red points in the middle correspond to the velocity component of v ~ −153 km s⁻¹. The lower red points refer to the velocity component of v ~−192 km s⁻¹.