Nonlinear optical and detonation properties of semiorganic nitrate crystal C6H14N2(NO3)3·H3O

Nonlinear optical (NLO) crystals, have attracted intense attentions in many related fields. Herein, we report a noncentrosymmetric (NCS)-centrosymmetric (CS) structure correlation between two semiorganic nitrates: C6H14N2(NO3)3·H3O (1,4-diazoniabicyclo-octane oxonium trinitrates, DHN) vs C6H14N2(NO3)2 (1,4-diazoniabicyclo-octane dinitrates, DN). Our single crystal data confirm the DHN structure as previously reported and we find that DHN changes to DN by heating at 125 °C for 5 h. In addition, the comprehensive NLO optical properties of DHN are studied: large birefringence (obv.: 0.110 at 589.3 nm), laser damage threshold (obv.: 2.5 × KDP), a phase matching behavior with the maximum intensity of 1.60 × KDP. Our first-principles calculations suggest that the NO3− anions contribute mainly to the band gap and to the second-harmonic generation (SHG). In addition, we reveal the detonation properties of DHN that are comparable to TNT: density (ρ) = 1.67 vs 1.65 g cm−3; detonation velocity (D) = 7.09 vs 6.66 km s−1; and detonation pressure (P) = 23.3 vs 21.3 GPa.