  In contrast to carbon, which forms long polymeric chains, all-nitrogen chains
are very unstable. Here we found that nitrogen and hydrogen directly react at
room temperature and pressures of about 35 GPa forming a mixture of nitrogen
backbone oligomers - chains of single-bonded nitrogen atom with the rest of the
bonds terminated with hydrogen atoms - as identified by IR absorption, Raman,
X-ray diffraction experiments and theoretical calculations. The pressure
required for the synthesis strongly decreases with temperature to about 20 GPa
at 550 K. At releasing pressures below about 10 GPa, the product transforms
into hydrazine. Our findings might open a way for the practical synthesis of
these extremely high energetic materials as the formation of nitrogen-hydrogen
compounds is favorable already at pressures above 2 GPa according to the
calculations.
