Data di Pubblicazione:
1997
Citazione:
New data on the structure of norbergite: Location of hydrogen by X-ray diffraction / F. Cámara. - In: CANADIAN MINERALOGIST. - ISSN 0008-4476. - 35:6(1997 Dec), pp. 1523-1530.
Abstract:
Two crystals of OH-rich norbergite from the Alpujarride Complex (Betic Cordilleras) have been analyzed, and their structure refined by single-crystal X-ray-diffraction analysis. The new 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, hydrogen atoms were located on the difference-Fourier map. Their position and the consequent structural constraints to the (OH)F-1 substitution suggest that OH-rich norbergite requires very high pressure to crystallize, thus explaining the normal occurrence of the fluorine-dominant compositions.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Electron-microprobe data; Humite group; Hydrogen; Norbergite; Structure refinement;
Elenco autori:
F. Cámara
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