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Title: High Pressure-Temperature Polymorphism of 1,1-diamino-2,2-dinitroethylene

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1162644
Report Number(s):
BNL-106589-2014-JA
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physics: Conference Series; Journal Volume: 500
Country of Publication:
United States
Language:
English

Citation Formats

Bishop, M., Chellappa, R., Liu, Z., Preston, D., Sandstrom, M., Dattelbaum, D., Vohra, Y., and Velisavljevic, N. High Pressure-Temperature Polymorphism of 1,1-diamino-2,2-dinitroethylene. United States: N. p., 2014. Web. doi:10.1088/1742-6596/500/5/052005.
Bishop, M., Chellappa, R., Liu, Z., Preston, D., Sandstrom, M., Dattelbaum, D., Vohra, Y., & Velisavljevic, N. High Pressure-Temperature Polymorphism of 1,1-diamino-2,2-dinitroethylene. United States. doi:10.1088/1742-6596/500/5/052005.
Bishop, M., Chellappa, R., Liu, Z., Preston, D., Sandstrom, M., Dattelbaum, D., Vohra, Y., and Velisavljevic, N. Wed . "High Pressure-Temperature Polymorphism of 1,1-diamino-2,2-dinitroethylene". United States. doi:10.1088/1742-6596/500/5/052005.
@article{osti_1162644,
title = {High Pressure-Temperature Polymorphism of 1,1-diamino-2,2-dinitroethylene},
author = {Bishop, M. and Chellappa, R. and Liu, Z. and Preston, D. and Sandstrom, M. and Dattelbaum, D. and Vohra, Y. and Velisavljevic, N.},
abstractNote = {},
doi = {10.1088/1742-6596/500/5/052005},
journal = {Journal of Physics: Conference Series},
number = ,
volume = 500,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 2014},
month = {Wed Jan 01 00:00:00 EST 2014}
}
  • Here, 1,1-diamino-2,2-dinitroethylene (FOX-7) is a low sensitivity energetic material with performance comparable to commonly used secondary explosives such as RDX and HMX. At ambient pressure, FOX-7 exhibits complex polymorphism with at least three structurally distinct phases (α, β, and γ). In this study, we have investigated the high pressure-temperature stability of FOX-7 polymorphs using synchrotron mid-infrared (MIR) spectroscopy. At ambient pressure, our MIR spectra and corresponding differential scanning calorimetry (DSC) measurements confirmed the known α → β (~110 °C) and β → γ (~160 °C) structural phase transitions; as well as, indicated an additional transition γ → δ (~210 °C),more » with the δ phase being stable up to ~251 degree C prior to decomposition. In situ MIR spectra obtained during isobaric heating at 0.9 GPa, revealed a potential α → β transition that could occur as early as 180 degree C, while β → β+δ phase transition shifted to ~300 °C with suppression of γ phase. Decomposition was observed slightly above 325 °C at 0.9 GPa..« less
  • In this study, the pressure–temperature (P–T) phase diagram of 1,1-diamino-2,2-dinitroethylene (FOX-7) was determined by in situ synchrotron infrared radiation spectroscopy with the resistively heated diamond anvil cell (DAC) technique. The stability of high-P–T FOX-7 polymorphs is established from ambient pressure up to 10 GPa and temperatures until decomposition. The phase diagram indicates two near isobaric phase boundaries at ~2 GPa (α → I) and ~5 GPa (I → II) that persists from 25 °C until the onset of decomposition at ~300 °C. In addition, the ambient pressure, high-temperature α → β phase transition (~111 °C) lies along a steep boundarymore » (~100 °C/GPa) with a α–β–δ triple point at ~1 GPa and 300 °C. A 0.9 GPa isobaric temperature ramping measurement indicates a limited stability range for the γ-phase between 0.5 and 0.9 GPa and 180 and 260 °C, terminating in a β–γ–δ triple point. With increasing pressure, the δ-phase exhibited a small negative dT/dP slope (up to ~0.2 GPa) before turning over to a positive 70 °C/GPa slope, at higher pressures. The decomposition boundary (~55 °C/GPa) was identified through the emergence of spectroscopic signatures of the characteristic decomposition products as well as trapped inclusions within the solid KBr pressure media.« less
  • The pressure-temperature (P-T) phase diagram of 1,1-diamino-2,2-dinitroethylene (FOX-7) was determined by in situ synchrotron infrared radiation spectroscopy with resistively heated diamond anvil cell (DAC) technique. The stability of high P-T FOX-7 polymorphs is established from ambient pressure up to 10 GPa and temperatures until decomposition. The phase diagram indicates two near isobaric phase boundaries at ~2 GPa (α → I) and ~5 GPa (I → II) that persists from 25 °C until the onset of decomposition at ~300 °C. In addition, the ambient pressure, high temperature α → β phase transition (~111 °C) lies along a steep boundary (~100 °C/GPa)more » with a α-β-δ triple point at ~1 GPa and 300 °C. A 0.9 GPa isobaric temperature ramping measurement indicates a limited stability range for the γ-phase between 0.5 – 0.9 GPa and 180 – 260 °C terminating in a β-γ-δ triple point. With increasing pressure, the δ-phase exhibited a small negative dT/dP slope (up to ~0.2 GPa) before turning over to a positive 70 degree C/GPa slope, at higher pressures. Furthermore, the decomposition boundary (~55 °C/GPa) was identified through the emergence of spectroscopic signatures of the characteristic decomposition products as well as trapped inclusions within the solid KBr pressure media.« less