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Crystal structures of quartz and magnesium germanate by profile analysis of synchrotron‐radiation high‐resolution powder data
Author(s) -
Will G.,
Bellotto M.,
Parrish W.,
Hart M.
Publication year - 1988
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889887011567
Subject(s) - germanate , synchrotron radiation , powder diffraction , quartz , resolution (logic) , crystal (programming language) , materials science , optics , bragg's law , diffraction , rietveld refinement , crystallography , mineralogy , chemistry , physics , programming language , optoelectronics , doping , artificial intelligence , computer science , composite material
High‐resolution synchrotron‐radiation powder data for quartz and Mg 2 GeO 4 , an olivine homologue, were obtained with a 365 mm long parallel‐slit collimator with 0.05° aperture. The crystal structures were refined using a pseudo‐Voigt profile fitting function and POWLS . Fourier maps were calculated from the measured structure factors of the germanate. The results for quartz were in good agreement with single‐crystal data and R (Bragg) increased from 1.35 to 2.20% as the number of reflections included in the refinement increased from 46 to 119; the e.s.d.'s of the positional parameters were 4 to 8 × 10 −4 . The germanate gave R (Bragg) 4.85% using 77 Miller planes and the e.s.d.'s were 4 to 42 × 10 −4 . Special attention was given to the profile fitting function and the non‐random particle distributions. The JCPDS Diffraction File Nos. will be reported in a later communication.