Metastable quasi-one-dimensional ensembles of nitrogen clusters N_8
  By means of ab initio and tight-binding calculations it is shown that metastable nitrogen clusters N_8 (boats) can form quasi-one-dimensional ensembles in which the nearest clusters N_8 are bound to each other by covalent bonds. Those ensembles are characterized by rather high energy barriers (~ 0.3 eV) that prevent the fission of the ensembles into isolated N_8 clusters and/or N_2 molecules. 
N.N.Degtyarenko, V.F.Elesin, L.A.Openov, A.I.Podlivaev