実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）Experimental Report
課題番号 Project No.

承認日 Date of Approval 2014/7/17
承認者 Approver Takanori Hattori
提出日 Date of Report 2014/7/14
装置責任者 Name of Instrument scientist

2014A0050

Takanori Hattori

実験課題名 Title of experiment
Structural variations of Ca(OD)2 at high pressure and hightemperature
実験責任者名 Name of principal investigator
Takaya Nagai

装置名 Name of Instrument/（BL No.）BL11
実施日 Date of Experiment
May 13, 2014 ～ May 18, 2014

所属 Affiliation
Faculty of Science, Hokkaido University, Japan
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.

deuterated portlandite, Ca(OD)2 : powder

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

Experimental
TOF neutron powder diffraction measurements of synthetic powder of deuterated portlandite, Ca(OD)2 werecarried out from 300 to 773 K at about 4.5 GPa at the PLANET beamline. Ca(OD)2 belongs to a trigonal crystalsystem and the cell dimensions are a=3.5826(6) Å and c=4.885(2) Å at ambient conditions. Generation of highpressure and high temperature (high P-T) can be performed by using the 6-ram big press “Atsuhime” installed atthe PLANET. 6 WC anvils truncated edge length of 10 mm, Al anvil guide, 17 mm cube ZrO2 pressure mediumand 4 mmϕ × 4 mm graphite tube heater were used for high P-T experiments. Incident beams were cut by slits ofW 2 mm × H 4 mm and radial collimators were set before detectors. Experimental P-T path was as follows. At
first, pressure was increased to 4.5 GPa at room temperature and then, temperature was increased to 773 K. Dataacquisition was carried out at each temperature condition (773, 673, 573, 473, 373 and 300 K) on the way to aroom temperature. Duration of each measurement was for 720000 kickers (about 10 hours).

2. 実験方法及び結果（つづき） Experimental method and results (continued)Results
TOF neutron powder diffraction data could be obtained at about 4 GPa and at 773, 673, 573, 473, 373 and 300 K, as
shown in Figure 1. Diffraction peaks are indexed as Ca(OD)2 and the unit cell parameters could be reasonably refined.
Variation of the unit cell dimensions are plotted at about 4 GPa as a function of temperature in Figure 2. It is quite
interesting that the change of the c/a values is very small and the increment of c/a is less than 0.002 from room
temperature to 773 K. This means that the behavior of the thermal expansion of Ca(OD)2 at about 4 GPa is rather isotropic,
although Xu et al.(2007) reported that the thermal expansion of Ca(OD)2 is anisotropic and the increment of c/a at ambientpressure is about 0.02 from room temperature to 643 K. This evidence can be explained by the behavior of deuterium
atoms located between CaO6 octahedral sheets in the Ca(OD)2 structure.

300K
373K
473K
573K
673K
773K

TOF (μsec)
Figure 1: Raw data of TOF neutron powder diffraction measured at about 4 GPa and at several temperatures.

Figure 2: Variation of the unit cell dimensions as a function of temperature at about 4 GPa.
References: Xu et al. (2007) J. Solid State Chem., 180, 1519-1525.