Predicted Pressure-Induced High-Energy-Density Iron Pentazolate Salts

Metal-pentazolate compounds as candidates for novel high-energy-density materials have attracted extensive attention in recent years.However,dehydrated pentazolate salts of transition metal iron are rarely reported.We predict two new iron pentazolate salts Fdd2-FeN10 and P1(No.1)-FeN10 using a constrained crystal search method based on first-principles calculations.We propose that the stable Fdd2-FeN_(10) crystal may be synthesized from FeN and N_(2) above 20 GPa,and its formation enthalpy is lower than the reported iron pentazolate salt(marked as P1(No.2)-FeN_(10)).Crystal P1(No.1)-FeN_(10) is composed of iron bispentazole molecules.Formation enthalpy,phonon spectrum and ab initio molecular dynamics calculations are performed to show their thermodynamic,mechanical and dynamic properties.Moreover,the high energy density(3.709 kJ/g,6.349 kJ/g)and good explosive performance indicate their potential applications as high-energy-density materials.