Geoscience reports of Shimane University

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Geoscience reports of Shimane University 22
2003-12-27 発行

Calculated X-ray power diffraction patterns for synthetic piemontite on the join Ca2Al3Si3O12(OH)-Ca2Mn〔3+〕3Si3O12(OH)

Nagashima, Mariko
Akasaka, Masahide
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Description
X-ray powder diffraction patterns of Ca_2Al_3Si_3O_<12>(OH)-Ca_2Mn^<3+>_3Si_3O_<12>(OH)series synthetic piemontites were simulated with the Rietan-2000 program to clarify the X-ray powder diffraction pattern of piemontite,using cell parameters,site occupancies and atomic positions refined by the X-ray RIETVELD method.The compositions of Ca_2Al_<3-p>Mn^<3+>_pSi_3O_<12>(OH)-piemontites used were p=0.5,0.75,1.0 and 1.25.The d-values of the strongest line in the simulated powder patterns show a nonlinear variation comparable to nonlinear changes in unit-cell parameters.The calculated powder patterns are very useful for indexing the Miller indices to each reflection in X-ray powder diffraction patterns of natural piemontite,to avoid misindexing and miscalculation of the unit-cell parameters.By comparison with these simulated X-ray powder patterns,we can evaluate the effects of preferred orientation in measured X-ray powder diffraction patterns,which is important for X-ray powder crystal structure analysis.
NCID
AA11455176