5-Nitrotetrazol and 1,2,4-Oxadiazole Methylene-Bridged Energetic Compounds: Synthesis, Crystal Structures and Performances

A new structural type for melt cast materials was designed by linking nitrotetrazole ring with 1,2,4-oxadiazole through a N-CH2-C bridge for the first time. Three N-CH2-C linkage bridged energetic compounds, including 3-((5-nitro-2H-tetrazol-2-yl) methyl)-1,2,4-oxadiazole (NTOM), 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-(trifluoromethyl)-1,2,4 -oxadiazole (NTOF) and 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-amine-1,2,4-oxadiazole (NTOA), were designed and synthesized through a two-step reaction by using 2-(5-nitro-2H-tetrazole -2-yl)acetonitrile as the starting material. The synthesized compounds were fully characterized by NMR (1H, 13C), IR spectroscopy and elemental analysis. The single crystals of NTOM, NTOF and NTOA were successfully obtained and investigated by single-crystal X-ray diffraction. The thermal stabilities of these compounds were evaluated by DSC-TG measurements, and their apparent activation energies were calculated by Kissinger and Ozawa methods. The crystal densities of the three compounds were between 1.66 g/cm3 (NTOA) and 1.87 g/cm3 (NTOF). The impact and friction sensitivities were measured by standard BAM fall-hammer techniques, and their detonation performances were computed using the EXPLO 5 (v. 6.04) program. The detonation velocities of the three compounds are between 7271 m/s (NTOF) and 7909 m/s (NTOM). The impact sensitivities are >40 J, and the friction sensitivities are >360 N. NTOM, NTOF and NTOA are thermally stable, with decomposition points > 240 °C. The melting points of NTOM and NTOF are 82.6 °C and 71.7 °C, respectively. Hence, they possess potential to be used as melt cast materials with good thermal stabilities and better detonation performances than TNT.

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Synthesis, Crystal structures, and Thermal behaviors of MBTO·nPhen with M=Co, Ni, Cu, Zn and Phen=1,10-Phenanthroline

10.3762/bxiv.2019.123.v1 ◽

2019 ◽

Author(s):

Jiaping Zhu ◽

Xiaoqing Yao ◽

Gang Wang ◽

Jianfeng Ban ◽

Dang Wu ◽

...

Keyword(s):

Differential Scanning Calorimetry ◽

Sandwich Structure ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Straightforward Manner ◽

Thermal Stabilities ◽

Exponential Factor ◽

X Ray ◽

Metal Atoms ◽

Apparent Activation Energies

The cocrystal of 1,10-phenanthrolin-1-ium 1-hydroxy-[5,5'-bitetrazol]-1'-olate (BTO·Phen) from 5,5′-bistetrazole-1,1′-diol dehydrate (BTO) and 1,10-Phenanthroline (Phen) was synthesized in a simple, straightforward manner and was characterized by IR, elemental analysis, and single-crystal X-ray diffraction of several salts (Ni2+ and Zn2+) were also given. The X-ray structures show that in the title compounds, the metal atoms are bonded to the nitrogen atom in the Phen ring and the oxygen atom in the bistetrazole ring to form the sandwich structure. Thermal stabilities of all title compounds were determined with Differential scanning Calorimetry (DSC), showing good thermostability. In addition, thermokinetic parameters including the apparent activation energies (E K and E O) and pre-exponential factor (A) were also calculated.

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Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽

10.3390/min11060611 ◽

2021 ◽

Vol 11 (6) ◽

pp. 611

Author(s):

Celia Marcos ◽

María de Uribe-Zorita ◽

Pedro Álvarez-Lloret ◽

Alaa Adawy ◽

Patricia Fernández ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Crystallite Size ◽

Archaeological Sites ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Infrared And Raman Spectroscopy ◽

First Time ◽

Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

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First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽

10.3390/cryst11020218 ◽

2021 ◽

Vol 11 (2) ◽

pp. 218

Author(s):

Carlos Alberto Ríos-Reyes ◽

German Alfonso Reyes-Mendoza ◽

José Antonio Henao-Martínez ◽

Craig Williams ◽

Alan Dyer

Keyword(s):

Natural Zeolite ◽

Scanning Electron Micrographs ◽

Total Sulfur ◽

Zeolite A ◽

X Ray Diffraction ◽

X Ray ◽

Mineral Phases ◽

The World ◽

Porosity And Permeability ◽

First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

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The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽

10.3390/ma14102623 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2623

Author(s):

Monika Wójcik-Bania ◽

Jakub Matusik

Keyword(s):

Total Pore Volume ◽

Cross Linking ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

The Cross ◽

Chain Lengths ◽

First Time ◽

Substituent Influence ◽

Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

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A novel and potentially scalable CVD-based route towards SnO2:Mo thin films as transparent conducting oxides

Journal of Materials Science ◽

10.1007/s10853-021-06269-3 ◽

2021 ◽

Author(s):

Tianlei Ma ◽

Marek Nikiel ◽

Andrew G. Thomas ◽

Mohamed Missous ◽

David J. Lewis

Keyword(s):

Thin Films ◽

Photoelectron Spectroscopy ◽

Mixed Valence ◽

Chemical Vapour ◽

X Ray Diffraction ◽

X Ray ◽

Conducting Oxides ◽

Valence States ◽

3 Omega ◽

First Time

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract

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The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs

Scientific Reports ◽

10.1038/s41598-021-81017-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mikolaj Grabowski ◽

Ewa Grzanka ◽

Szymon Grzanka ◽

Artur Lachowski ◽

Julita Smalc-Koziorowska ◽

...

Keyword(s):

Quantum Wells ◽

High Temperatures ◽

Point Defects ◽

X Ray Diffraction ◽

Helium Ions ◽

X Ray ◽

Sapphire Substrates ◽

Transmission Electron ◽

The Impact ◽

Ingan Quantum Wells

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

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Reactive Dual Magnetron Sputtering: A Fast Method for Preparing Stoichiometric Microcrystalline ZnWO4 Thin Films

Surfaces ◽

10.3390/surfaces4020013 ◽

2021 ◽

Vol 4 (2) ◽

pp. 106-114

Author(s):

Yannick Hermans ◽

Faraz Mehmood ◽

Kerstin Lakus-Wollny ◽

Jan P. Hofmann ◽

Thomas Mayer ◽

...

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Photoelectron Spectroscopy ◽

Fast Method ◽

X Ray Diffraction ◽

X Ray ◽

Glass Substrates ◽

Post Annealing ◽

Rf Signal ◽

First Time

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.

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Monoclinic and Orthorhombic NaMnO2 for Secondary Batteries: A Comparative Study

Energies ◽

10.3390/en14051230 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1230

Author(s):

Jessica Manzi ◽

Annalisa Paolone ◽

Oriele Palumbo ◽

Domenico Corona ◽

Arianna Massaro ◽

...

Keyword(s):

Structural Parameters ◽

Reversible Capacity ◽

Beta Phase ◽

X Ray Diffraction ◽

Positive Electrodes ◽

Detailed Structural Analysis ◽

Physico Chemical ◽

Sodium Batteries ◽

The Impact ◽

First Time

In this manuscript, we report a detailed physico-chemical comparison between the α- and β-polymorphs of the NaMnO2 compound, a promising material for application in positive electrodes for secondary aprotic sodium batteries. In particular, the structure and vibrational properties, as well as electrochemical performance in sodium batteries, are compared to highlight differences and similarities. We exploit both laboratory techniques (Raman spectroscopy, electrochemical methods) and synchrotron radiation experiments (Fast-Fourier Transform Infrared spectroscopy, and X-ray diffraction). Notably the vibrational spectra of these phases are here reported for the first time in the literature as well as the detailed structural analysis from diffraction data. DFT+U calculations predict both phases to have similar electronic features, with structural parameters consistent with the experimental counterparts. The experimental evidence of antisite defects in the beta-phase between sodium and manganese ions is noticeable. Both polymorphs have been also tested in aprotic batteries by comparing the impact of different liquid electrolytes on the ability to de-intercalated/intercalate sodium ions. Overall, the monoclinic α-NaMnO2 shows larger reversible capacity exceeding 175 mAhg−1 at 10 mAg−1.

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Crystalline and Electrical Properties of Ferroelectric Silver Niobate-tantalate thin Films

MRS Proceedings ◽

10.1557/proc-655-cc11.5.1 ◽

2000 ◽

Vol 655 ◽

Cited By ~ 1

Author(s):

Jung-Hyuk Koh ◽

S.I. Khartsev ◽

Alex Grishin ◽

Vladimir Petrovsky

Keyword(s):

Temperature Stability ◽

Frequency Dispersion ◽

Processing Temperature ◽

High Temperature Stability ◽

X Ray Diffraction ◽

Ferroelectric State ◽

X Ray ◽

Ferroelectric Hysteresis ◽

First Time

AbstractFor the first time AgTa0.38Nb0.62O3 (ATN) films have been grown on the La0.7Sr0.3CoO3 (LSCO)/LaAlO3 single crystal as well as onto Pt80Ir20 (PtIr) polycrystalline substrate. Comprehensive X-ray diffraction analyses reveal epitaxial quality of ATN and LSCO films on the LaAlO3(001) substrate, while ATN/PtIr films have been found to be (001) preferentially oriented. Dielectric spectroscopy performed for ATN films and bulk ceramics in a wide temperature range 77 to 420 K shows the structural monoclinic M1-to-monoclinic M2 phase transition occurs in films at the temperature 60 °C lower than in ceramics. The tracing of the ferroelectric hysteresis P-E loops indicates the ferroelectric state in ATN films at temperatures below 125 K and yields remnant polarization of 0.4 μC/cm2 @ 77 K. Weak frequency dispersion, high temperature stability of dielectric properties as well as low processing temperature of 550 °C make ATN films to be attractive for various applications.

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Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424618500633 ◽

2018 ◽

Vol 22 (09n10) ◽

pp. 814-820

Author(s):

Yingying Jia ◽

Ling Xu ◽

Bangshao Yin ◽

Mingbo Zhou ◽

Jianxin Song

Keyword(s):

Nickel Complex ◽

High Resolution Mass Spectrometry ◽

Dihedral Angles ◽

X Ray Diffraction ◽

Extinction Coefficients ◽

X Ray ◽

H Nmr ◽

First Time ◽

Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

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