Mechanical Properties and Pressure Effects on the Crystal Structure of Azetidine Derivative Trans (1‐Nitro‐2,3‐Bis ((Nitrooxy)Methyl)Azetidin‐2‐yl) Ethyl Nitrate by Single‐Crystal X‐Ray Diffractometry and Density Functional Theory

ABSTRACT Understanding the interrelationship between crystal structure and mechanical properties provides insight into tailoring materials for improved performance and safety. We present the crystal structure and mechanical properties of newly synthesized azetidine derivative trans (1‐nitro‐2,3‐bis ((nitrooxy)methyl) azetidin‐2‐yl) ethyl nitrate (AD2, C 7 H 11 N 5 O 11 ) obtained by single‐crystal x‐ray diffractometry and density functional theory (DFT) and report the effects of pressure on structure and mechanical properties in the pressure range between ambient pressure and 10 GPa. AD2 comprises an azetidine moiety functionalized with a nitro group on the nitrogen ring atom and three, near‐planar ethyl nitric ester groups on the carbon atoms adjacent and opposite the nitrogen atom. Intermolecular van der Waals H···O and O···O interactions contribute mostly to the crystal packing of AD2 at ambient pressure, whereas C–H···O hydrogen bonding and H···O and O···O interactions contribute to the crystal packing of AD2 at higher pressures. AD2 is structurally stable and does not undergo any phase transition in the pressure range studied. A fourth‐order Birch–Murnaghan (B–M) equation‐of‐state fit of the pressure‐volume data yields an isothermal bulk modulus B B–M = 12.9 (8) GPa with pressure derivative B ′ = 6.7 (3), in agreement with our DFT finite‐strain calculations (12.25 GPa). In addition, we use the calculated bulk and shear moduli values to derive values for the AD2 Young's modulus, shear, and longitudinal velocities and compare them to those of other energetic materials.