Upon compression to 60 GPa, reaction between nitrogen and hydrogen was found, where four kinds of hydronitrogen compounds were stabilized: H 2 N−NH 2 (hydrazine), H 2 N−NH−NH−NH 2 (N4-II), H 2 N−N=N−NH 2 (labeled N4-I), and H 2 N−NH−N(NH 2 )−NH−NH 2 (N6), in ratios of 7:3:1:1.
Source: wiktionary