New data on the structure of norbergite; location of hydrogen by X-ray diffraction

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Authors:Camara, Fernando
Author Affiliations:Primary:
CNR, Centro di Studio per la Cristallochimica e la Cristallografia, Pavia, Italy
Volume Title:Canadian Mineralogist
Source:The Canadian Mineralogist, Vol.35(Part 6), p.1523-1530. Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada. ISSN: 0008-4476
Publication Date:1997
Note:In English with French summary. 27 refs.; illus., incl. 5 tables
Summary:Two crystals of OH-rich norbergite from the Alpujarride complex, Betic Cordilleras, Spain, have been examined by EPMA and their structure refined by single-crystal XRD to R 1.43. These data confirm the earlier refinement on a composition near the F end-member, and add new insight to the crystal chemistry of this humite-group mineral. In particular, H atoms were located on the difference-Fourier map. Their position and the consequent structure constraints on the OH [] F substitution suggest that OH-norbergite requires very high P to crystallize, thus explaining the normal occurrence of the F-dominant variety. [R.A.H.]
Sections:Crystal structure
Subsections:Specific structures: silicates
Subjects:Chemical composition; Crystal structure; Fluorides; Halides; Humite; Hydrogen; Measurement; Nesosilicates; New data; Norbergite; Orthosilicates; Silicates; Substitution; X-ray diffraction data; Alpujarras; Andalusia Spain; Betic Cordillera; Europe; Iberian Peninsula; Southern Europe; Spain; Humite group
Abstract Numbers:98M/3502
Record ID:1998052601
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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