As reported in 2019, magnesium monocyanoacetylide (MgC₃N or Mg–C≡C–C≡N) was detected toward IRC +10216 by Cernicharo and co-workers using the IRAM 30m telescope. The detection was based upon experimental and theoretical work by Cabezas et al. also published in 2019. Magnesium monocyanoacetylide has a dipole moment that exceeds 6 D, which enhances its rotational spectrum compared to molecules with smaller dipole moments. While Petrie and co-workers had assigned certain doublet lines in IRC +10216 to MgC₃N in 2003, subsequent analysis determined that those lines should be assigned to C₆H.

Like MgC₃N, most of the magnesium-containing molecules detected to date are linear doublet species, including MgNC, MgCN, MgCCH, and MgC₄H (to be featured next month). Magnesium forms linear X–Mg–Y compounds, such as HMgNC (detected in 2013), because its 3s² pair of electrons is recoupled.