Polynitrogen chemistry.: Synthesis, characterization, and crystal structure of surprisingly stable fluoroantimonate salts of N5+

The new N-5(+) salt, N5+SbF6-, was prepared from N2F+SbF6- and HN3 in anhydrous HF solution. The white solid is surprisingly stable, decomposing only at 70 degreesC, and is relatively insensitive to impact. Its vibrational spectrum exhibits all nine fundamentals with frequencies that are in excellent agreement with the theoretical calculations for a five-atomic V-shaped ion of C-2v. symmetry, The N5+Sb2F11- salt was also prepared, and its crystal structure was determined. The geometry previously predicted for free gaseous N-5(+) from theoretical calculations was confirmed within experimental error. The Sb2F11- anions exhibit an unusual geometry with eclipsed SbF4 groups due to interionic bridging with the N-5(+) cations. The N-5(+) cation is a powerful one-electron oxidizer. It readily oxidizes NO, NO2, and Br-2 but fails to oxidize Cl-2, Xe, or O-2.