The structure of the low-temperature phase V of ammonium nitrate, ND4NO3

Ahtee, Maija; Smolander, Kimmo; Lucas, B. W.; Hewat, A.W.

doi:10.1107/s0108270183005806

Cited by 27 publications

(21 citation statements)

References 3 publications

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“…Ammonium nitrate (NH 4 NO 3 ) crystallizes in several polymorphic forms, which consists of NH 4 + and NO 3 -ions [1]- [6]. The room-temperature phase of ammonium nitrate is designated as phase IV, which is stable between 255 and 305 K [1].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on Proton Transfer and Energetics in Ammonium Nitrate (NH4NO3)n Cluster System

Takeuchi¹,

Takeda²

2014

IJAPM

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Abstract-We study the mechanism and energetics of proton transfer (PT) in ammonia-nitric acid systems by employing ab initio calculations. PT does not occur in the single ammonium nitrate unit (NH 3 -HNO 3 ; monomer) without the application of an external electric field. In contrast, PT is energetically favorable in oligomers (NH 4 NO 3 ) n=2~8 due to the internal polarization -resulting in the ammonium and nitrate ions, NH 4 + · · · NO 3 -. Additionally, we study the energetics of ammonium nitrate oligomerization using simple energy decomposition. The classical electrostatic interaction plays a principal role in the studied oligomerization, whereas the charge transfer interaction is not significant. Consequently, PT in the ammonium nitrate oligomer system enhances the internal electrostatic interaction, resulting in an ionic form with remarkable stability even in the gas phase.Index Terms-Ab initio calculation, ammonium nitrate oligomers, energetic stabilization, proton transfer.

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Section: Introductionmentioning

confidence: 99%

Theoretical Study on Proton Transfer and Energetics in Ammonium Nitrate (NH4NO3)n Cluster System

Takeuchi¹,

Takeda²

2014

IJAPM

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“…The orthorhombic structure (Pnma) of the AN III phase with a = 0.77184 nm, b = 0.58447 nm and c = 0.0.71624 nm, was reported to be stable between (32 and 84)°C [9,10]. The low-temperature AN IV and AN V phases were reported as orthorhombic structure with space group Pmmn [stable (À16 to 32)°C] [8,11] and orthorhombic structure with space group Pccn (stable below À16°C) [12,13], respectively. Feick [14] determined the vapor pressure of liquid ammonium nitrate from (190 to 240)°C using a modified boiling point apparatus.…”

Section: Introductionmentioning

confidence: 99%

The vaporization of NH4NO3

Chien

Chandra

Lau

et al. 2010

The Journal of Chemical Thermodynamics

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“…[2][3][4][5][6][7][8][9][10][11] These phases are designated with Roman numerals in the widely used system 12 where I is the phase stable at high temperatures, which then converts to phase II upon cooling, and so on. Projections of four of the AN phases ͑V, IV, II, and I͒ on the a -b planes are illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics studies of melting and solid-state transitions of ammonium nitrate

Velardez

Alavi

Thompson

2004

The Journal of Chemical Physics

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Molecular dynamics simulations are used to calculate the melting point and some aspects of high-temperature solid-state phase transitions of ammonium nitrate (AN). The force field used in the simulations is that developed by Sorescu and Thompson [J. Phys. Chem. A 105, 720 (2001)] to describe the solid-state properties of the low-temperature phase-V AN. Simulations at various temperatures were performed with this force field for a 4 x 4 x 5 supercell of phase-II AN. The melting point of AN was determined from calculations on this supercell with voids introduced in the solid structure to eliminate superheating effects. The melting temperature was determined by calculating the density and the nitrogen-nitrogen radial distribution functions as functions of temperature. The melting point was predicted to be in the range 445 +/- 10 K, in excellent agreement with the experimental value of 442 K. The computed temperature dependences of the density, diffusion, and viscosity coefficient for the liquid are in good agreement with experiment. Structural changes in the perfect crystal at various temperatures were also investigated. The ammonium ions in the phase-II structure are rotationally disordered at 400 K. At higher temperatures, beginning at 530 K, the nitrate ions are essentially rotationally unhindered. The density and radial distribution functions in this temperature range show that the AN solid is superheated. The rotational disorder is qualitatively similar to that observed in the experimental phase-II to phase-I solid-state transition.

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The structure of the low-temperature phase V of ammonium nitrate, ND4NO3

Cited by 27 publications

References 3 publications

Theoretical Study on Proton Transfer and Energetics in Ammonium Nitrate (NH4NO3)n Cluster System

Theoretical Study on Proton Transfer and Energetics in Ammonium Nitrate (NH4NO3)n Cluster System

The vaporization of NH4NO3

Molecular dynamics studies of melting and solid-state transitions of ammonium nitrate

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