Explosives under pressure—the crystal structure of γ-RDX as determined by high-pressure X-ray and neutron diffraction

Davidson, Alistair J.; Oswald, Iain D. H.; Francis, D. J.; Lennie, Alistair R.; Marshall, William G.; Millar, David I. A.; Pulham, Colin R.; Warren, John E.; Cumming, Adam S.

doi:10.1039/b715677b

Cited by 125 publications

(155 citation statements)

References 21 publications

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“…1a) has been widely studied both experimentally [38][39][40][41][42][43][44][45] and theoretically [35,[46][47][48][49][50][51][52]. There are four known polymorphs of RDX, denoted a [53], b [54], e [55], and c [56]. The a-phase is the stable form at room temperature and atmospheric pressure and has received the most study.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of the Collapse of a Cylindrical Pore in the Energetic Material α-RDX

Eason

Sewell

2015

J. dynamic behavior mater.

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Molecular dynamics simulations were used to study the shock-induced collapse of cylindrical pores in oriented single crystals of the energetic material a-1,3,5-trinitroperhydro-1,3,5-triazine (a-RDX). The shock propagation direction was parallel to the [100] crystal direction and the cylinder axis of the initially 35.0 nm diameter pore was parallel to [010]. Features of the collapse were studied for Rankine-Hugoniot shock pressures P s = 9.71, 24.00, and 42.48 GPa. Pore collapse for the weak shock is dominated by visco-plastic deformation in which the pore pinches shut without jet formation and with little penetration of the upstream material into the downstream pore wall. For the strong shock the collapse is hydrodynamiclike and results in the formation of a jet that penetrates significantly into the downstream pore wall. Material flow during collapse was characterized by examining the spread and mixing of sets of initially contiguous molecules and evolution of local velocity fields. Local disorder during collapse was assessed using time autocorrelation functions for molecular rotation. Energy deposition and localization was studied using spatial maps of temperature and pressure calculated as functions of time.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulations of the Collapse of a Cylindrical Pore in the Energetic Material α-RDX

Eason

Sewell

2015

J. dynamic behavior mater.

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“…Although this model is appealing, primarily in its simplicity, the authors admit that no account has been made for thermochemistry, particularly the enthalpies of formation, or for the effects of other stimuli such as heat, static shock or friction. As has been demonstrated in this and previous studies, the effects of extreme conditions on the crystal structures of energetic materials can be dramatic, and often induce phase transitions [71][72][73]. It is therefore essential to obtain structural information on such materials at a range of temperatures and pressures.…”

Section: Discussionmentioning

confidence: 99%

Structural characterization of sodium azide and sodium bifluoride at high pressures

Millar

Barry

Marshall

et al. 2014

Zeitschrift Für Kristallographie Crystalline Materials

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This paper reports the structural characterization of sodium azide and sodium bifluoride (hydrogenfluoride) at elevated pressures using neutron powder diffraction. Compression of sodium azide at 294 K induces a transition from the β-phase to the α-phase. This structure responds to increasing pressure by progressive tilting of the azide groups. Compression of the α-form to 3.33 GPa at 393 K results in a phase transition to the tetragonal γ-phase (space group I4/mcm), which is isostructural with the azides of the heavier Group 1 elements and features square-antiprism co-ordination of the cations. On decompression at ambient temperature, the γ-phase reverts to the α-phase, but with substantial peak broadening indicative of significant strain within the recovered sample. Compression of sodium bifluoride (NaDF 2 -I to 0.66 GPa at ambient temperature resulted in the formation of NaDF 2 -II, which adopts an orthorhombic, marcasite-like (space group Pnnm) structure. Further compression to 4.58 GPa resulted in a transition to NaDF 2 -III, which adopts the archetypal I4/mcm structure shared by the heavier alkali metal bifluorides and γ-NaN 3 .

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“…In recent years, a lot of efforts have been laid both in experiment and theoretical calculation in this respect. Diamond anvil cell, which can generate a pressure of hundreds of GPa, was used to study the changes of materials at high pressure, such as cell parameters, phase transition, and so on [19,20]. Compared with the experiment, theoretical calculations show much more details to help us to understand the changing mechanism.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of BTF/TNA cocrystal: Effects of hydrostatic pressure and temperature

et al. 2015

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Cocrystallization is a promising technique for the design and preparation of new explosives, and the stability of cocrystal is highly concerned by the researchers. In order to make a better understanding of the behavior of cocrystal under the extreme conditions, DFT (density functional theory) calculation is performed to investigate the effect of hydrostatic pressure on geometrical and electronic structures of the cocrystal BTF (benzotrifuroxan)/TNA (2,4,6-trinitroaniline). When the hydrostatic pressure is applied, the lattice constants, volume, density and total energy change gradually except at the pressures of 40 GPa and 79e83 GPa. It is noteworthy that new chemical bonds form when the pressure is up to 83 GPa. The band gap of the cocrystal becomes smaller when the pressure is applied, and finally the cocrystal shows a characteristic of metal. The mechanical property of cocrystal is calculated by MD (molecular dynamics) simulation. The results show that the cocrystal has a better ductibility at low temperature, and has the best tenacity at 295 K.

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Explosives under pressure—the crystal structure of γ-RDX as determined by high-pressure X-ray and neutron diffraction

Abstract: Explosives under pressurethe crystal structure of γ-RDX as determined by high-pressure X-ray and neutron di raction COMMUNICATION Swift et al. Structure of a lead urate complex and its e ect on the nucleation of monosodium urate monohydrate CrystEngComm www.rsc.org/crystengcomm

Cited by 125 publications

References 21 publications

Molecular Dynamics Simulations of the Collapse of a Cylindrical Pore in the Energetic Material α-RDX

Molecular Dynamics Simulations of the Collapse of a Cylindrical Pore in the Energetic Material α-RDX

Structural characterization of sodium azide and sodium bifluoride at high pressures

Theoretical study of BTF/TNA cocrystal: Effects of hydrostatic pressure and temperature

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