The Triply Deprotonated Acetonitrile Anion CCN^3- Stabilized in a Solid

The unprecedented, fully deprotonated form of acetonitrile, the acetonitriletriide anion CCN^3- , is experimentally realized for the first time in the stabilizing bulk host framework of the Ba₅ [TaN₄ ][C₂ N] nitridometalate via a one-pot synthesis from the elements under moderate conditions (920 K). The molecular structure of this long-sought acetonitrile derivative is confirmed by X-ray diffraction, as well as NMR, IR, and Raman spectroscopy. The anion is isoelectronic to the CO₂ molecule, and, in contrast to acetonitrile (H₃ C-C≡N), the electron pairs are shifted towards two double bonds, that is, [C=C=N]^3- .