The crystal structure of a new mixed valence arsenic(III,V)oxoacid H6As3+
 7As5+
 7O31

Studies on the physicomechanical properties of commonly used energetic materials (EMs) that were pursued by the group led by Professor John Sherwood are reviewed in this paper. The studies ranged from the growth of high quality single crystals and the characterization of their defect and dislocation structures, mechanical testing, through to the study of polymorphism of EM crystals and fundamental aspects of crystallization processes in general. The work performed led to the definition of good growth conditions for all the EMs studied and to the full characterization of the defect structure, slip systems, and hardness properties of cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN). Partial characterization of the defect structures and hardness properties of cyclotetramethylene tetranitramine (HMX) and 2,4,6-trinitrotoluene (TNT) was also achieved. Additionally, fundamental crystal growth and polymorph information were defined, allowing a deeper understanding of the crystallization and crystal structure of TNT. In addition to the general review, some thoughts were given as to possible future routes for further study that could suitably utilize the complementary nature of established and modern techniques.

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Low temperature phase transition induced biaxial negative thermal expansion of 2,4-dinitroanisole

Takahashi

Tamura

2015

CrystEngComm

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The crystal structure of 2,4-dinitroanisole (24DNAN) is known to have two polymorphic structures (Z′ = 2 and Z′ = 1, hereafter referred to as α-form and β-form, respectively) and the oxygen atoms of the nitro group(s) of both polymorphs have been found to be disordered over two positions at 298 K. In the thermal behaviour studies of 24DNAN, the β-form showed a phase transition at 264.5 K on cooling. To investigate this phase transition variable-temperature single-crystal X-ray diffraction measurements were carried out.The β angle for the β-form dramatically changed from 90.190°(298 K) to 96.716°(100 K). The length of the b axis shows negative thermal expansion, 13.741(5) to 13.810(5) Å (with a change in temperature from 298 K to 100 K). The thermal expansion coefficients along the principal axes X1, X2, and X3 are −31Ĳ6), −15Ĳ7) and 262(20) MK −1 (261-100 K), respectively. 24DNAN showed an unusual biaxial NTE induced by a low temperature phase transition.

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The crystal structure of a new mixed valence arsenic(III,V)oxoacid H₆As³⁺ ₇As⁵⁺ ₇O₃₁

Cited by 3 publications

References 23 publications

2,4 Dinitroanisole (DNAN)

2,4 Dinitroanisole (DNAN)

John N. Sherwood: Studies of Energetic Materials

Low temperature phase transition induced biaxial negative thermal expansion of 2,4-dinitroanisole

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The crystal structure of a new mixed valence arsenic(III,V)oxoacid H6As3+ 7As5+ 7O31

Cited by 3 publications

References 23 publications

2,4 Dinitroanisole (DNAN)

2,4 Dinitroanisole (DNAN)

John N. Sherwood: Studies of Energetic Materials

Low temperature phase transition induced biaxial negative thermal expansion of 2,4-dinitroanisole

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Product

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The crystal structure of a new mixed valence arsenic(III,V)oxoacid H₆As³⁺ ₇As⁵⁺ ₇O₃₁