Crystal Structure of Gamma Nitrogen

Abstract

We have determined by x-ray diffreaction that high-pressure gamma nitrogen is tetragonal with two molecules per unit cell in special position $f$ of space group $\frac{P{4}_2}{\mathrm{mnm}}$. At an average pressure and temperature of 4015±145 atm and 20.5±1.7 K, respectively, the unit cell dimensions are $a=3.957\mathrm{}$ Å and $c=5.109\mathrm{}$ Å, giving a molar volume of 24.09 ${\mathrm{cm}}^3$ which is in good agreement with the value 24.05 ${\mathrm{cm}}^3$ taken from piston-displacement measurements.