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Title: In situ X-ray study of ammonia borane at high pressure

Abstract

In situ synchrotron X-ray diffraction experiments of ammonia borane synthesized using sonication assisted direct reaction (sodium borohydride and ammonium formate) were performed under high pressures up to 23 GPa at ambient temperature and up to 4 GPa at elevated temperatures (300 K-505 K). At ambient temperature, one first order phase transition (I4mm to Cmc2{sub 1}) was observed at 1.3 GPa and one second order phase transition was observed at about 5 GPa. Fitting the measured volumetric compression data to the third order Birch-Murnaghan equation of state reveals a bulk modulus of K = 9.3 {+-} 0.4 GPa (K{prime} = 4.8) for the I4mm phase, K = 11.9 {+-} 0.5 GPa (K{prime} = 4.6) for the Cmc2{sub 1} phase below 5 GPa, and K = 37 {+-} 4 GPa (K{prime} = 4.6) for pressure above 5 GPa. There is a 6% volume drop at the first order phase transition. Transition pressures from I4mm to Cmc2{sub 1} phases were determined at elevated temperatures. The phase boundary has a negative Clapeyron slope of -1.67 MPa/K. The experiments also reveal a new structural transition when temperature increases to 450 K at 4 GPa.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
DOE - Office Of Science
OSTI Identifier:
1004626
Report Number(s):
BNL-94540-2011-JA
Journal ID: ISSN 0360-3199; IJHEDX; R&D Project: LS001; KC0401030; TRN: US1100980
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
International Journal of Hydrogen Energy
Additional Journal Information:
Journal Volume: 35; Journal Issue: 20; Journal ID: ISSN 0360-3199
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 60 APPLIED LIFE SCIENCES; AMBIENT TEMPERATURE; AMMONIA; BORANES; BOROHYDRIDES; COMPRESSION; DIRECT REACTIONS; SODIUM; SYNCHROTRONS; X-RAY DIFFRACTION

Citation Formats

Chen, J, Kao, C, Couvy, H, Liu, H, Drozd, V, Daemen, L, and Zhao, Y. In situ X-ray study of ammonia borane at high pressure. United States: N. p., 2010. Web. doi:10.1016/j.ijhydene.2010.07.085.
Chen, J, Kao, C, Couvy, H, Liu, H, Drozd, V, Daemen, L, & Zhao, Y. In situ X-ray study of ammonia borane at high pressure. United States. doi:10.1016/j.ijhydene.2010.07.085.
Chen, J, Kao, C, Couvy, H, Liu, H, Drozd, V, Daemen, L, and Zhao, Y. Sat . "In situ X-ray study of ammonia borane at high pressure". United States. doi:10.1016/j.ijhydene.2010.07.085.
@article{osti_1004626,
title = {In situ X-ray study of ammonia borane at high pressure},
author = {Chen, J and Kao, C and Couvy, H and Liu, H and Drozd, V and Daemen, L and Zhao, Y},
abstractNote = {In situ synchrotron X-ray diffraction experiments of ammonia borane synthesized using sonication assisted direct reaction (sodium borohydride and ammonium formate) were performed under high pressures up to 23 GPa at ambient temperature and up to 4 GPa at elevated temperatures (300 K-505 K). At ambient temperature, one first order phase transition (I4mm to Cmc2{sub 1}) was observed at 1.3 GPa and one second order phase transition was observed at about 5 GPa. Fitting the measured volumetric compression data to the third order Birch-Murnaghan equation of state reveals a bulk modulus of K = 9.3 {+-} 0.4 GPa (K{prime} = 4.8) for the I4mm phase, K = 11.9 {+-} 0.5 GPa (K{prime} = 4.6) for the Cmc2{sub 1} phase below 5 GPa, and K = 37 {+-} 4 GPa (K{prime} = 4.6) for pressure above 5 GPa. There is a 6% volume drop at the first order phase transition. Transition pressures from I4mm to Cmc2{sub 1} phases were determined at elevated temperatures. The phase boundary has a negative Clapeyron slope of -1.67 MPa/K. The experiments also reveal a new structural transition when temperature increases to 450 K at 4 GPa.},
doi = {10.1016/j.ijhydene.2010.07.085},
journal = {International Journal of Hydrogen Energy},
issn = {0360-3199},
number = 20,
volume = 35,
place = {United States},
year = {2010},
month = {7}
}