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1

Development of explosives detection method based on FAIMS (Field Asymmertric Ion Mobility Spectrometry) and thin layer chromatography (TLC)

Tomaszewski Waldemar, Perchaluk Paweł, Maksimowski Paweł, Gołofit Tomasz

Materiały Wysokoenergetyczne

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2021

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T. 13

112--122

EN

A new method of hyphenation of thin layer chromatography (TLC) and field asymmetric ion mobility spectrometry (FAIMS), is presented. Coupling chromatography with spectrometry enables the simultaneous separation and identification of individual species. During chromatographic experiments the elution was carried out using normal- and reversed-phase systems. The detection was performed with MO-2M and PILOT-M handheld detectors. The chromatographic bands were located using ultraviolet detection and a spray reagent containing diphenylamine. The bands containing explosives were separated and placed in thermal desorbers of the detectors. They were applied as vapour intensifiers. During experiments, a more effective way of desorption from TLC sheets using a conventional dry block heater was demonstrated. The best results were obtained using the MO-2M detector an normal-phase separations. By applying such separation, it was possible to detect 10 μg of trinitrotoluene, hexogen, pentaerythritol tetranitrate and CL-20 on TLC plates.

PL

W pracy przedstawiono połączenie dwóch metod: chromatografii cienkowarstwowej (TLC) oraz spektrometrii FAIMS. Połączenie (sprzężenie) metody chromatograficznej np. z metodą spektrometryczną pozwala na szybki rozdział mieszaniny i identyfikację jej składników. Do rozdziałów chromatograficznych zastosowano normalny lub odwrócony układ faz, jako detektory użyto spektrometry MO-2M i PILOT-M. Pasma chromatograficzne lokalizowano w promieniowaniu ultrafioletowym lub po zastosowaniu odczynnika wywołującego z difenyloaminą. Po lokalizacji na rozwiniętych płytkach pasm chromatograficznych wycinano ich fragmenty, które desorbowano termicznie w fabrycznych desorberach urządzeń lub na zaprojektowanym stanowisku z podgrzewaczem laboratoryjnym. Desorpcję termiczną zastosowano w celu zwiększenia emisji par substancji wybuchowych z płytek krzemionkowych. Stosując detektor MO-2M oraz płytki krzemionkowe rozwijane w normalnym układzie faz zidentyfikowano w rozdzielonych pasmach chromatograficznych, zawierających po 10 μg, heksogenu, trotylu, pentrytu oraz CL-20.

2

Study of the Effect of DINA on the Polymorphic Transition of ε-CL-20 in Composite Modified Double Base Propellants

Wu Zongkai, Zheng Wei, Pei Jiangfeng, Chen Zhiqun, Zhang Jun, Song Xiuduo, Wang Jiangning, Zhang Dongxiang, Zhao Fengqi

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 2

165--182

EN

Abstract: The polymorphic transition of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.05,9.03,11]dodecane (CL-20) is influenced by the materials and conditions used in the preparation of propellants, and limits the application of ε-CL-20 in solid propellants. In the present work, the effect of dinitroxydiethylnitramine (DINA) on the polymorphic transition of ε-CL-20 in CMDB propellants was investigated by Raman spectroscopy and the Calvet microcalorimeter method. The performance of propellants with CL-20 as affected by DINA was studied by the theoretical prediction of their energetic parameters, stability, combustion, and mechanical tests, respectively. The results showed that the polymorphic transition temperature of ε-CL-20 to α-CL-20 can be reduced to 75 °C by DINA. Expansion of the crystal volume during the process of the ε-CL-20 to α-CL-20 transition will produce obvious cracks in the surface of the crystals. NC/NG can inhibit the effect of DINA on the polymorphic transition of ε-CL-20. The theoretically predicted results indicated that adding DINA will not lower the energy level of CMDB propellants containing CL-20. The DSC and VST results showed that CL-20 has good compatibility and thermal stability with DINA. The burning rate tests revealed that adding DINA decreases the burning rates of CMDB propellants containing CL-20. Mechanical property testing showed that adding DINA can clearly improve the mechanical properties of CMDB propellants containing CL-20. The results of these investigations suggested that DINA has no effect on the crystalline stability of ε-CL-20 in the solventless extrusion process, which contributes to a significant understanding of practical applications and provides guidance for applied research on the use of CL-20 in propellants.

3

Preparation and Characterization of CL-20 Based Composites by Compressed Air Spray Evaporation

Xu Wen Zheng, Peng Jin Yu, Wang Jie, Li Hao, Wang Jing Yu

Central European Journal of Energetic Materials

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2020

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Vol. 17, no. 1

66--84

EN

Ultrafine CL-20 particles and three CL-20-based composites were prepared by a compressed air spray evaporation method. All samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and mechanical sensitivity instruments. The results indicated that the thermal stabilities of the CL-20-based composites are better than that of ultrafine CL-20, and that the mechanical sensitivities of ultrafine CL-20 is lower than those of CL-20-based composites. The thermal stability and safety properties of CL-20/Estane 5703 are better than the other samples.

4

Preparation of MCM-41 Supported Benzene Sulphonic Acid, a Catalyst for the Synthesis of CL-20 from TAIW

Chen Shixiong, Yang Chaofei, Qian Hua, Liu Dabin, Kai Wang, Li Rui

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 3

343--359

EN

Pure MCM-41 anchored benzene sulphonic acid (BSA/MCM-41), an efficient heterogeneous catalyst, was prepared for the synthesis of CL-20 from TAIW. The prepared catalysts were fully characterized by FTIR, XRD, TEM, TG, N2 adsorption techniques, elemental analysis and acidity tests. It was observed that the catalyst (BSA/MCM-41) retained the mesoporous structure like MCM-41, exhibited excellent thermal stability and high activity. Compared with a blank, the high catalytic activity promoted shorter reaction times by a factor of 3/5. In addition, this catalyst could be reused at least five times without significant loss of its catalytic potential. Moreover, the BSA/MCM-41 catalyst exhibited an optimal catalytic performance, with a high to excellent yield of CL-20 (92.5%) with a purity of 98.3%, under the optimum synthesis conditions.

5

Fabrication of Nano- and Micron- Sized Spheres of CL-20 by Electrospray

Yan S., Li M., Sun L., Jiao Q., Huang R.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 4

572--589

EN

The application of hexanitrohexaazaisowurtzitane (CL-20) in energetic materials will be expanded by its use as superfine particles. A method of fabricating nano- and micron-sized spheres of CL-20 by using electrospray is discussed. The effects of the precursor solution and the experimental conditions on the morphology and the crystal phase of the CL-20 particles are introduced. A variety of solvents was used to dissolve raw CL-20 for the preparation of the precursor solution with different CL-20 contents. The conductivity and viscosity of the precursor solutions were tested before the electrospray process. The electrostatic parameters were adjusted by changing the voltage and the distance between the nozzle and the plate. The morphology, crystal phase, mechanical sensitivity, density, and thermal stability of the raw CL-20 and the as-sprayed CL-20 samples were determined using scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry (DSC). Furthermore, the density and the mechanical sensitivity were tested for the raw and the as-sprayed CL-20. DSC tests were conducted to compare the thermal stability and reactivity of the samples.

6

Analysis of the Thermal Behaviour of CL-20, Potassium Perchlorate, Lithium Perchlorate and Their Admixtures by DSC and TG

Zhang J.-J., Guo X.-J., Jiao Q.-J., Zhang H.-L., Li H.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 1

115--130

EN

The thermal decomposition characteristics of CL-20, potassium perchlorate (KP), lithium perchlorate (LP), a CL-20/KP mixture, and a CL-20/LP mixture were studied using thermogravimetry-differential scanning calorimetry (TG-DSC). The DSC curves for KP exhibited three endothermic peaks and one exothermic peak. The first two endothermic peaks correspond to the rhombic-cubic transition and the fusion of KP, respectively, the third indicates the fusion of KCl, while the exothermic peak is attributed to the decomposition of KP. The DSC curves obtained from LP showed four endothermic peaks and one exothermic peak. The first two endothermic peaks indicate the loss of adsorbed water and water of crystallization, while the third and fourth are associated with the fusion of LP and LiCl, respectively; the exothermic peak is due to the decomposition of LP. The presence of KP had little effect on the thermal decomposition of CL-20 while the addition of LP increased the temperature at which CL-20 exhibits an exothermic peak. In addition, the thermal decomposition of LP appeared to be catalyzed by the presence of CL-20.

7

Temperature-dependent Shock Initiation of CL-20-based High Explosives

Pi Z., Chen L., Wu J.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 2

361--374

EN

To investigate the effects of temperature on the shock initiation characteristics of hexanitrohexaazaisowurtzitane (CL-20), shock initiation experiments on heated C-1 explosive (94% epsilon phase CL-20, and 6% binder, by weight) were performed at temperatures of 20 °C, 48 °C, 75 °C, 95 °C, 125 °C, 142 °C, and 175 °C. An explosive driven flyer device was used to initiate the C-1 charges and manganin pressure gauges were embedded in the C-1 specimen to record the pressure changes with time. Our results show that C-1 becomes more sensitive as the temperature is increased from 20 °C to 95 °C. The ε to γ phase transition in CL-20 occurs at 125 °C; C-1 with CL-20 in the γ phase at 142 °C is less shock sensitive than C-1 with CL-20 in the ε phase at 95 °C or 75 °C. Compared with C-1 at 142 °C, C-1 at 175 °C shows a dramatic increase in shock sensitivity. An ignition and growth reactive flow model was used to simulate the shock initiation of C-1 at various temperatures, and the parameters were obtained by fitting the experimental data. With this parameter set, the shock initiation characteristics of C-1 for temperatures between 20 °C and 175 °C can be derived.

8

Purification of Hexabenzylhexaazaisowurtzitane

Gołofit T., Maksimowski P.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 4

1038--1050

EN

Hexabenzylhexaazaisowurtzitane (HBIW) is produced by a condensation reaction of benzylamine with glyoxal in suitable organic solvents in the presence of protonic acid catalysts. Impurities have to be removed prior to the subsequent stages of the synthesis of CL-20. The effectiveness of HBIW purification by recrystallization from a variety of solvents has been studied here. This method was compared with a novel approach suggested for HBIW purification that consists of prolonged heating of the crude product in boiling methanol. This new purification method allows the product to be prepared in satisfactory purity, it is simple and easily performed on a large-scale.

9

Properties of the Gamma-Cyclodextrin/CL-20 System

Maksimowski P., Rumianowski T.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 1

217--229

EN

Cyclodextrin (CD) is a cyclic compound with a spatial structure in the shape of a toroid. It is characterized by specific properties. The outer portion of the structure has hydrophilic properties, while the cavity of the toroid is hydrophobic. This enables cyclodextrin to form inclusion complexes with the enclosure of lipophilic molecules in the interior. This paper presents the results of attempts to form a complex of γ-CD/CL-20. This study determined unambiguously that a γ-CD with CL-20 complex in a mole ratio 1:1 is formed as a result of mixing of solutions of γ-CD and CL-20. This conclusion was corroborated by FTIR, 1H NMR, UV-Vis spectroscopic techniques and by measurement of the density of the complex obtained. The resulting complex of γ-CD/CL-20 is characterized by much lower sensitivity to friction and impact than CL-20 itself.

10

Experimental Studies on Advanced Sheet Explosive Formulations Based on 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and Hydroxyl Terminated Polybutadiene (HTPB), and Comparison with a RDX-based System

Jangid S. K., Talawar M. B., Singh M. K., Nath T., Sinha R. K.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 1

135--147

EN

The present investigation reports the use of 2,4,6,8,10,12-hexanitro2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) in sheet explosive formulations. In this study, hydroxyl terminated polybutadiene (HTPB) based sheet explosives were prepared incorporating the powerful explosive CL-20 as a partial replacement for hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX). The effects of incorporating CL-20 on the performance, sensitivity, thermal and mechanical properties of the sheet explosive compositions are reported. Sheet explosive formulation containing 80% of RDX and 20% of HTPB-binder was studied as control sample. HTPBbinder consisted of 12% HTPB, 2.9% dioctyl adipate (DOA) and 5.1% dioctyl phthalate (DOP). HTPB was cured with 4,4’-methylene diphenyl di-isocyanate (MDI) to form urethane linkages. The incorporation of 20% of CL-20 in place of RDX led to a remarkable increase in the velocity of detonation (VOD), of the order of 7680 m/s, and to better mechanical properties in terms of tensile strength (1.14 MPa) compared to the control formulation [RDX /HTPB-binder (80/20)]. The 20% CL-20 incorporated sheet explosive formulation also showed remarkable increases in impact and shock sensitivity. Thermal analysis of the sheet explosive compositions has also been carried out using differential scanning calorimetry (DSC).

11

Concerning the shock sensitivity of cyclic nitramines incorporated into a polyisobutylene matrix

Pelikán W., Zeman S., Yan Q. L., Erben M., Elbeih A., Akštein Z.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 2

219--235

EN

Two types of plastic bonded explosives (PBXs) based on ε-2,4,6,8,10,12hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-HNIW, CL-20), and PBXs based on 1,3,5-trinitro-1,3,5-triazinane (RDX), β-1,3,4,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) and cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (bicycloHMX, BCHMX) were prepared using a polyisobutylene binder with dioctylsebacate (DOS) as plasticizer, i.e. a C4 matrix. One version of the ε-HNIW PBX is a product with reduced sensitivity (RS-ε-HNIW). All these PBXs, referenced respectively as RS-ε-HNIW-C4, ε-HNIW-C4, RDX-C4, HMX-C4 and BCHMX-C4, were tested using the Small Scale Gap Test according to STANAG 4488. The results of the gap test on the PBXs with RDX, β-HMX and BCHMX correspond to the impact sensitivities of the original crystalline nitramines. This is not entirely valid for ε-HNIW. In other words, PBXs with RS-ε-HNIW cannot achieve as low a shock sensitivity as would be expected from the differences obtained from the impact sensitivities between RDX, β-HMX and BCHMX, on the one hand, and RS-εHNIW on the other. It is shown that the morphological stability of RS-ε-HNIW in the C4 matrix is insufficient. However, further development and use of RS-ε-HNIW as a filler of PBXs would seem to be both desirable and beneficial. Despite the relatively high impact sensitivity of crystalline BCHMX, the shock sensitivity of its analogous C4 PBX is already good, and comparable with that of RS-ε-HNIW.

12

Metody syntezy i właściwości fizykochemiczne 2,4,6,8,10,12-heksanitro-2,4,6,8,10,12-heksaazaizowurcytanu (HNIW)

Borkowski J., Czerwińska M.

Wiadomości Chemiczne

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2013

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[Z] 67, 1-2

93--109

EN

Explosives have a very rich history of its creation. This history dates back to the ninth century, when the Chinese invented a black powder. In the end of the twentieth century, the first nitroamine polycyclic cage structure was obtained. The representative of this group is 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaizowurtzitane (HNIW, Cl-20). HNIW has recently been the subject of an interest as one of the strongest explosive material. As nitroamine, HNIW is compared to the other energetic materials: RDX i HMX [1, 2]. Researchers [5, 6] showed, that it is possible to replace a variety of typical explosives by HNIW and thanks to that obtain compositions with higher densities, heat of explosion and higher velocity of detonation. In the published papers [7-13, 16] there were presented six polymorphs of HNIW: αβγδε with specific stabilities and structural characteristics. Unfortunately, there is no a direct method of obtaining HNIW. There are at least four steps needed to obtain HNIW. The first step is the synthesis of HBIW [20-22]. The next one is debenzylation reaction of HBIW [20-29] in order to remove the benzyl groups. The third step is removal of the two other benzyl groups and replace them by nitroso, formyl or acetyl groups [20, 24, 30, 32]. In the final step there is a nitration of HNIW precursors [31-37]. The HNIW seems to be a promising explosive and it can replace other currently used energetic materials. However, using HNIW is limited due to the complicated and expensive technology of its production. Therefore, research groups carried out new syntheses of HNIW to eliminated these problem. In this article, review of the literature on the physicochemical properties and synthetic methods for HNIW were presented. The basic physical and explosive parameters of HNIW were summarized. The spatial structure was presented and polymorphs of HNIW were characterized. The methods for obtaining HNIW and intermediate products needed for its preparation were described. The methods of preparation of different HNIW polymorphs were also given.

13

Thermally induced damage in hexanitrohexaazaisowurtzitane

Tian Q., Yan G., Sun G., Huang C., Xie L., Chen B., Huang M., Li H., Liu X., Wang J.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 3

359--369

EN

The evolution of the microstructure of hexanitrohexaazaisowurtzitane (CL-20) after a thermal stimulus plays a key role in the performance of CL-20. In the current work, microstructural variations of CL-20 caused by thermal treatment were investigated by X-ray diffraction, in situ variable-temperature optical microscopy, atom force microscopy, and small-angle X-ray scattering. A wave-like process, an abrupt volume expansion, movement, and fragmentation of CL-20 particles during phase transition were observed. After the phase transition (160 °C) the CL-20 sample acquired a very rough surface with numerous dimple depressions, and during the thermal decomposition stage (200 °C) a large number of voids were produced in both the bulk and the surface of the CL-20.

14

Quantitative analysis of α-CL-20 polymorphic impurity in ε-CL-20 using Dispersive Raman Spectroscopy

Ghosh M., Venkatesan V., Sikder N., Sikder A. K.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 3

419--438

EN

α-CL-20 polymorphic impurity in ε-CL-20 studies have been carried out using Dispersive Raman Spectroscopy. ε-, β-, α- and γ-CL-20 polymorphs were produced using crystallization methods with sample recovery from the solution being >90%, and chemical purity of about 99%. The polymorphs prepared were characterized using Dispersive Raman Spectroscopy over the Raman shift region of 100-3500 cm-1 using a 514 nm argon ion laser. The experimental studies were supported by ab initio computations performed at B3LYP level using a 6-31+G** basis set. The computed vibrational frequencies of the CL-20 conformers correspond to the ε, β and α or γ-CL-20 polymorphs when compared with the observed frequencies. α-CL-20 shows a distinct feature at 280 cm-1 as compared with those of the ε-CL-20 polymorph. Using Dispersive Raman Spectroscopy, a linear relationship was demonstrated for the absolute peak height and absolute peak area ratio of α-CL-20 versus the weight percent of α-CL-20. This method enables a detection limit of this polymorphic impurity down to 2 wt%.

15

Friction Sensitivity of the ε-CL-20 Crystals Obtained in Precipitation Process

Szczygielska J., Chlebna S., Maksimowski P., Skupiński W.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 2

117-130

EN

The purpose of this work was to obtain samples of CL-20 by precipitation process in a solvent/nonsolvent system, under variable process parameters such as: antisolvent kind, time of nonsolvent addition, stirrer speed, mass of seeded crystals of ε-CL-20. Received samples were studied in the aspect of their sensitivity to friction. As the results of the crystallization processes were prepared crystals of different sizes and shapes depend on applied parameters. It was affirmed, that applied antisolvent has essential influence on type of received crystals. CL-20 crystals of cuboid shape and sizes of 80-200 μm were obtained by recrystallization from ethyl acetate/chloroform. As the result of the recrystallization from ethyl acetate/xylene crystals with rounded edges were obtained. Crystals, from both samples, were mostly single and showed the lowest sensitivity to friction. Also, the crystals of irregular shape and sharp-edged agglomerates were obtained from systems with n-heptane, isooctane, cyclohexane and toluene, which revealed the highest friction sensitivities.

16

Study of the Interaction of Polynitro Compounds with Transition Metals Coordination Complexes with 1,5-Pentamethylenetetrazole as a Ligand

Ilyushin M. A., Bachurina I. V., Smirnov A. V., Tselinsky I. V., Shugalei I. V.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 1

33-46

EN

Perchlorate complexes of d-metals with tetrazole-containing ligands are proposed for application both as explosives for safe initiation systems and as modifers of burning rate for propellants. However, the problem of compatibility of organic polynitro compounds with the complexes has not yet been solved. In the present article the results of investigation of the infuence of perchlorate complexes of cobalt, copper and nickel with 1,5-pentamethylentetrazole as a ligand on thermal decomposition of energetic materials ranging from 1,1-diamino-2,2- dinitroethylene (FOX-7), to cyclic cyclotetramethylenetetranitroamine (HMX) and caged hexanitrohexaazaizowurtzitane (CL-20) have been reported. Thermal stability of the individual compounds and their mixtures with coordination complexes has been assessed on the basis of differential thermal analysis and the study of ignition temperatures after 5-second delay. The fraction of the complexes in the formulations with polynitro compounds amounted to ~10%.