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Title: Heating induced structural and chemical behavior of KD{sub 2}PO{sub 4} in the 25 °C–215 °C temperature range

Abstract

We have used powder x-ray diffraction (XRD) to investigate the structural and chemical modifications undergone by KD{sub 2}PO{sub 4} (DKDP) upon heating from room temperature to 215 °C. Full-profile (Le Bail) analysis of our temperature-resolved data shows no evidence of polymorphic structural transitions or deuterium–hydrogen isotope exchange occurring below T{sub s} = 185 °C. The lattice parameters of DKDP vary smoothly upon heating to T{sub s} and are 0.2% to 0.6% greater than those of its isostructural hydrogenated counterpart KH{sub 2}PO{sub 4} (KDP). In addition, XRD isotherms collected at T{sub s} demonstrate the structural and chemical stability of the title compound at this temperature over a 10.5 h time period. Upon further heating, however, the tetragonal DKDP phase becomes unstable, as evidenced by its transition to a monoclinic DKDP modification and eventual chemical decomposition via dehydration. - Highlights: • Structural and chemical behavior of KD{sub 2}PO{sub 4} is investigated upon heating to 215 °C • No polymorphic transitions or deuterium-hydrogen isotope exchange below T{sub s} = 185 °C • KD{sub 2}PO{sub 4} is structurally and chemically stable at T{sub s} over a 10.5 h time period • KD{sub 2}PO{sub 4} chemically decomposes via dehydration upon heating above T{sub d} =more » 195 °C.« less

Authors:
; ; ;
Publication Date:
OSTI Identifier:
22285079
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 83; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DECOMPOSITION; DEHYDRATION; DEUTERATION; DEUTERIUM; LATTICE PARAMETERS; MODIFICATIONS; MONOCLINIC LATTICES; POTASSIUM PHOSPHATES; TEMPERATURE RANGE 0273-0400 K; X-RAY DIFFRACTION

Citation Formats

Botez, Cristian E., E-mail: cbotez@utep.edu, Morris, Joshua L., Encerrado Manriquez, Andres J., and Anchondo, Adan. Heating induced structural and chemical behavior of KD{sub 2}PO{sub 4} in the 25 °C–215 °C temperature range. United States: N. p., 2013. Web. doi:10.1016/J.MATCHAR.2013.06.010.
Botez, Cristian E., E-mail: cbotez@utep.edu, Morris, Joshua L., Encerrado Manriquez, Andres J., & Anchondo, Adan. Heating induced structural and chemical behavior of KD{sub 2}PO{sub 4} in the 25 °C–215 °C temperature range. United States. doi:10.1016/J.MATCHAR.2013.06.010.
Botez, Cristian E., E-mail: cbotez@utep.edu, Morris, Joshua L., Encerrado Manriquez, Andres J., and Anchondo, Adan. 2013. "Heating induced structural and chemical behavior of KD{sub 2}PO{sub 4} in the 25 °C–215 °C temperature range". United States. doi:10.1016/J.MATCHAR.2013.06.010.
@article{osti_22285079,
title = {Heating induced structural and chemical behavior of KD{sub 2}PO{sub 4} in the 25 °C–215 °C temperature range},
author = {Botez, Cristian E., E-mail: cbotez@utep.edu and Morris, Joshua L. and Encerrado Manriquez, Andres J. and Anchondo, Adan},
abstractNote = {We have used powder x-ray diffraction (XRD) to investigate the structural and chemical modifications undergone by KD{sub 2}PO{sub 4} (DKDP) upon heating from room temperature to 215 °C. Full-profile (Le Bail) analysis of our temperature-resolved data shows no evidence of polymorphic structural transitions or deuterium–hydrogen isotope exchange occurring below T{sub s} = 185 °C. The lattice parameters of DKDP vary smoothly upon heating to T{sub s} and are 0.2% to 0.6% greater than those of its isostructural hydrogenated counterpart KH{sub 2}PO{sub 4} (KDP). In addition, XRD isotherms collected at T{sub s} demonstrate the structural and chemical stability of the title compound at this temperature over a 10.5 h time period. Upon further heating, however, the tetragonal DKDP phase becomes unstable, as evidenced by its transition to a monoclinic DKDP modification and eventual chemical decomposition via dehydration. - Highlights: • Structural and chemical behavior of KD{sub 2}PO{sub 4} is investigated upon heating to 215 °C • No polymorphic transitions or deuterium-hydrogen isotope exchange below T{sub s} = 185 °C • KD{sub 2}PO{sub 4} is structurally and chemically stable at T{sub s} over a 10.5 h time period • KD{sub 2}PO{sub 4} chemically decomposes via dehydration upon heating above T{sub d} = 195 °C.},
doi = {10.1016/J.MATCHAR.2013.06.010},
journal = {Materials Characterization},
number = ,
volume = 83,
place = {United States},
year = 2013,
month = 9
}
  • By definition, the critical dimensions or mass (the size beyond which temperature increases without limit) of a self-heating chemical cannot be measured directly. Hence, experimental work must be done with supercritical masses whose allowable size depends upon the time available to the experimenter and upon the risk of eventual explosion which can be tolerated. As an aid to planning such experiments, an IBM 704 computer was used to find the numerical solutions of Fourier's equation, including a power generation term and associated initial and boundary conditions, thus simulating the theoretical dynamic behavior of a mass of a self-heating chemical. Themore » program was used to simulate the behavior of spheres of a material similar to a mixture of NH/sub 4/NO/sub 3/ and fuel oil. (auth)« less
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