Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6
As AgN 3 is an excellent reagent for the synthesis of polyazides35 and halogen azides both in the gas phase36 and in solution37,38, we suggest that the reaction of AgN 3 with XN 3 (X = halogen) is a viable route to N 6 (Fig. 1b). The reactions were conducted in either a quartz tube or a U-trap by flowing gaseous Cl 2 through solid AgN 3 under reduced pressure at room temperature (see the ‘Synthesis details’ section in Methods and Supplementary Fig. 1). Apart from the known bands of ClN 3 (ref. 3