The baddeleyite-type high pressure phase of Ca(OH)2

M. Kunz; K. Leinenweber; J. B. Parise; T. C. Wu; W. A. Bassett; K. Brister; D. J. Weidner; M. T. Vaughan; Y. Wang

The baddeleyite-type high pressure phase of Ca(OH)₂

M. Kunz^*, K. Leinenweber, J. B. Parise, T. C. Wu, W. A. Bassett, K. Brister, D. J. Weidner, M. T. Vaughan, Y. Wang

^*Corresponding author for this work

NSRC - Northwestern Synchrotron Research Center - LS CAT

Research output: Contribution to journal › Article › peer-review

36 Scopus citations

Abstract

A phase transition from Ca(OH)₂ I (portlandite) to Ca(OH)₂ II at high pressure and temperature has been confirmed, using in situ x-ray diffraction in a multianvil high pressure device (DIA). The structure was determined at 9.5 GPa and room temperature from data collected after heating the sample at 300°C at 7.2 GPa in a diamond anvil cell. Both the Le Bail fit and preliminary Rietveld refinement suggest that the new phase, which reverts to Ca(OH)₂ I during pressure release, has a structure related to that of baddeleyite (ZrO₁); it is monoclinic (P2₁/c) with a = 4.887(2), b = 5.834(2), c = 5.587(2), β = 99.74(2)°. The coordination number of Ca increases from six to seven (5 + 2) across the transition. At 500°C, the phase boundary is bracketed at 5.7 ± 0.4 GPa by reversal experiments performed in the DIA.

Original language	English (US)
Pages (from-to)	311-319
Number of pages	9
Journal	High Pressure Research
Volume	14
Issue number	4-5
State	Published - Dec 1 1996

Keywords

Ca(OH)
High pressure
Phase transition
X-ray diffraction

ASJC Scopus subject areas

Condensed Matter Physics

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title = "The baddeleyite-type high pressure phase of Ca(OH)2",

abstract = "A phase transition from Ca(OH)2 I (portlandite) to Ca(OH)2 II at high pressure and temperature has been confirmed, using in situ x-ray diffraction in a multianvil high pressure device (DIA). The structure was determined at 9.5 GPa and room temperature from data collected after heating the sample at 300°C at 7.2 GPa in a diamond anvil cell. Both the Le Bail fit and preliminary Rietveld refinement suggest that the new phase, which reverts to Ca(OH)2 I during pressure release, has a structure related to that of baddeleyite (ZrO1); it is monoclinic (P21/c) with a = 4.887(2), b = 5.834(2), c = 5.587(2), β = 99.74(2)°. The coordination number of Ca increases from six to seven (5 + 2) across the transition. At 500°C, the phase boundary is bracketed at 5.7 ± 0.4 GPa by reversal experiments performed in the DIA.",

keywords = "Ca(OH), High pressure, Phase transition, X-ray diffraction",

author = "M. Kunz and K. Leinenweber and Parise, {J. B.} and Wu, {T. C.} and Bassett, {W. A.} and K. Brister and Weidner, {D. J.} and Vaughan, {M. T.} and Y. Wang",

year = "1996",

month = dec,

day = "1",

language = "English (US)",

volume = "14",

pages = "311--319",

journal = "High Pressure Research",

issn = "0895-7959",

publisher = "Taylor and Francis Ltd.",

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TY - JOUR

T1 - The baddeleyite-type high pressure phase of Ca(OH)2

AU - Kunz, M.

AU - Leinenweber, K.

AU - Parise, J. B.

AU - Wu, T. C.

AU - Bassett, W. A.

AU - Brister, K.

AU - Weidner, D. J.

AU - Vaughan, M. T.

AU - Wang, Y.

PY - 1996/12/1

Y1 - 1996/12/1

N2 - A phase transition from Ca(OH)2 I (portlandite) to Ca(OH)2 II at high pressure and temperature has been confirmed, using in situ x-ray diffraction in a multianvil high pressure device (DIA). The structure was determined at 9.5 GPa and room temperature from data collected after heating the sample at 300°C at 7.2 GPa in a diamond anvil cell. Both the Le Bail fit and preliminary Rietveld refinement suggest that the new phase, which reverts to Ca(OH)2 I during pressure release, has a structure related to that of baddeleyite (ZrO1); it is monoclinic (P21/c) with a = 4.887(2), b = 5.834(2), c = 5.587(2), β = 99.74(2)°. The coordination number of Ca increases from six to seven (5 + 2) across the transition. At 500°C, the phase boundary is bracketed at 5.7 ± 0.4 GPa by reversal experiments performed in the DIA.

AB - A phase transition from Ca(OH)2 I (portlandite) to Ca(OH)2 II at high pressure and temperature has been confirmed, using in situ x-ray diffraction in a multianvil high pressure device (DIA). The structure was determined at 9.5 GPa and room temperature from data collected after heating the sample at 300°C at 7.2 GPa in a diamond anvil cell. Both the Le Bail fit and preliminary Rietveld refinement suggest that the new phase, which reverts to Ca(OH)2 I during pressure release, has a structure related to that of baddeleyite (ZrO1); it is monoclinic (P21/c) with a = 4.887(2), b = 5.834(2), c = 5.587(2), β = 99.74(2)°. The coordination number of Ca increases from six to seven (5 + 2) across the transition. At 500°C, the phase boundary is bracketed at 5.7 ± 0.4 GPa by reversal experiments performed in the DIA.

KW - Ca(OH)

KW - High pressure

KW - Phase transition

KW - X-ray diffraction

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