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3-Nitro-1,2,4-triazole-5-one (NTO) has received wide attention and has applications owing to its excellent detonation performance and low sensitivity. A new crystal form of NTO was prepared via the solvent evaporation method and named γ-NTO. Its crystal properties were studied through single-crystal X-ray diffraction, and the results indicated that the unit cell of γ-NTO belongs to the monoclinic space group Pc, with eight molecules in the single unit cell. The density of this crystal is calculated to be 1.907 g cm−3, which is higher than that of β-NTO and similar to that of α-NTO. The crystal morphology was calculated to be a polygonal shape with a symmetrical growth pattern using the reactive force field. Based on the analysis of reactive molecular dynamics, the thermal decomposition mechanism of different crystal forms of NTO was elucidated, and the results showed that γ-NTO demonstrates higher gas production, providing a successful way to enhance detonation performance. The results of IR and differential thermal analysis (DTA) support the above conclusions. [ABSTRACT FROM AUTHOR]

Highlights: A Cr5Te8@expanded graphite heterostructure is fabricated by chemical vapor deposition, exhibiting remarkable microwave absorption performance with a minimum reflection loss of up to − 57.6 dB at a thin thickness of only 1.4 mm under a low filling rate of 10%. Density functional theory calculations deeply reveal the polarization loss mechanism triggered by heterogeneous interfaces. The heterostructure coating displays a remarkable radar cross section reduction of 31.9 dB m2, demonstrating a great electromagnetic microwave scattering ability and radar stealth capability. Two-dimensional (2D) transition metal chalcogenides (TMCs) hold great promise as novel microwave absorption materials owing to their interlayer interactions and unique magnetoelectric properties. However, overcoming the impedance mismatch at the low loading is still a challenge for TMCs due to the restricted loss pathways caused by their high-density characteristic. Here, an interface engineering based on the heterostructure of 2D Cr5Te8 and graphite is in situ constructed via a one-step chemical vapor deposit to modulate impedance matching and introduce multiple attenuation mechanisms. Intriguingly, the Cr5Te8@EG (ECT) heterostructure exhibits a minimum reflection loss of up to − 57.6 dB at 15.4 GHz with a thin thickness of only 1.4 mm under a low filling rate of 10%. The density functional theory calculations confirm that the splendid performance of ECT heterostructure primarily derives from charge redistribution at the abundant intimate interfaces, thereby reinforcing interfacial polarization loss. Furthermore, the ECT coating displays a remarkable radar cross section reduction of 31.9 dB m2, demonstrating a great radar microwave scattering ability. This work sheds light on the interfacial coupled stimulus response mechanism of TMC-based heterogeneous structures and provides a feasible strategy to manipulate high-quality TMCs for excellent microwave absorbers. [ABSTRACT FROM AUTHOR]

Although NTO is unquestionably acidic, its potential to corrode weaponry and associated reaction mechanisms remain puzzling. Here, ab initio molecular dynamics (AIMD) with explicit solvation and "slow-growth" sampling approaches are utilized to identify the key steps involved in NTO induced metal corrosion. Our results affirm that the acidity of NTO originates from the lower dehydrogenation barrier of the N4 site compared to the N1 site (0.28 vs. 0.37 eV). Furthermore, NTO has the strongest adsorption on Fe(110) in a nitro-dissociation manner, revealed by using density functional theory (DFT) calculations. Notably, under the catalysis of Fe(110) and hydrogen shuttling, both NTO and its anion can realize the "nitro-to-amino" reaction within 4 ps, but the reduction barrier of the anion is higher. The surface species (*O and *OH) produced by the "nitro-to-amino" reaction serve as corrosion precursors and exacerbate the observed surface iron oxide formation in the experiments. Consequently, the surface corrosion products and azole rings, which are difficult to further decompose under mild conditions, act as a barrier to mitigate the corrosion rate. This work not only unveils a crucial issue in the application of NTO, but also highlights the importance of metal surface and hydrogen bonding in the corrosion process. Our research provides guidance for elaborating the mechanism of NTO induced corrosion at the microscopic level; it may hold for other acidic organic molecules as well. Such understanding can help in establishing corresponding protective measures. [ABSTRACT FROM AUTHOR]

C6H5N11O6, monoclinic, P21/n (no. 14), a = 13.463(5) Å, b = 6.526(2) Å, c = 14.068(5) Å, β = 95.961(5)°, V = 1229.3(7) Å3, Z = 4, Rgt(F) = 0.0417, wRref(F2) = 0.1067, T = 153 K.

C6H6N12O12 · 0.33 H2O, orthorhombic, Pbca (no. 61), a = 9.5152(7) Å, b = 13.2551(11) Å, c = 23.6736(18) Å, V = 2985.8(7) Å3, Z = 4, Rgt(F) = 0.0727, wRref(F2) = 0.1268, T = 293(2) K.