MgCCH is an acetylide formed
by replacing one of the H atoms in acetylene with a metal atom. Other known magnesium astromolecules include
magnesium isocyanide (MgNC),
magnesium cyanide (MgCN), and
hydromagnesium isocyanide (HMgCN).
No other acetylide has been detected in the ISM, although the rotational spectrum
NaCCH has been