Quadrupole Coupling in Alkali Metal Amides MNH2 (X̃1A1): An Experimental and Computational Study

•First experimental determination of the quadrupole coupling in metal amide species.•First FTMmmW measurements (22–58 GHz) of LiNH2 and NaNH2.•Further evidence for strong ionic bonding in alkali amide molecules.•First computed structure for KNH2 (X~1A1) with a modern basis set for future work.