Experimental detection of tetranitrogen

Tetranitrogen (N-4), which has been the subject of great theoretical interest, has been prepared from the N-4(+) cation and positively detected as a gaseous metastable molecule with a lifetime exceeding 1 microsecond in experiments based on neutralization-reionization mass spectrometry. An examination of the geometry of N-4(+) and the fragmentation pattern of the N-14(2) N-15(2) neutral molecule has revealed that the latter is characterized by an open-chain geometry with two distinct, closely bound N-2 units joined by a longer weaker bond.