Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
American Mineralogist house ad
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
American Mineralogist; October 1997; v. 82; no. 9-10; p. 1014-1018
This Article
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Order Hardcopy of Full Text via AGI/GeoRef
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Hoffmann, C.
Right arrow Articles by Giester, G.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Acentric structure (P3) of bechererite, Zn 7 Cu(OH) 13 [SiO(OH) 3 SO 4 ]

Christina Hoffmann, Thomas Armbruster, and Gerald Giester

Universitat Bern, Laboratorium fur Chemische und Mineralogische Kristallographie, Bern, Switzerland

The crystal structure of bechererite from the Tonopah-Belmont mine, Arizona, was reinvestigated using a single-crystal X-ray diffractometer (MoKalpha radiation) equipped with a CCD area detector. The structure was refined in space group P3 (a = 8.319(2), c = 7.377(1) A) with 1247 unique reflections up to (sintheta )/lambda = 0.65 leading to R1 = 2.7%, wR2 = 6.4%. In agreement with the previously reported centric structure (P3), bechererite is composed of (001) brucite-like sheets formed by edge-sharing (Zn,Cu)O 6 octahedra and 1/7 ordered octahedral vacancies. The layers are connected parallel to c by ditetrahedral (Zn,Cu) 2 (OH) 7 units. Due to the attractive force of a weak hydrogen bond, the bridging O atom of the ditetrahedral unit is displaced from the threefold axis. A characteristic feature of the structure is isolated tetrahedra, which connect only with one apex to the octahedral sheet. The acentric structure (P3) reveals ordering between SiO(OH) 3 and SO 4 tetrahedra yielding characteristic distortions of the neighboring (Zn,Cu)O 6 octahedra caused by bond-valence requirements of the shared O atoms. The [SiO(OH) 3 ] (super 1-) tetrahedron is only 70(1)% occupied and is partly substituted by tetrahedral [O 4 H 7 ] (super 1-) clusters. The existence of H 2 O molecules in the [O 4 H 7 ] (super 1-) cluster is supported by FTIR spectroscopy.

This record provided courtesy of AGI/GeoRef.




This article has been cited by other articles:


Home page
 Can MineralHome page
E. Sokolova, F. C. Hawthorne, V. V. Karpenko, A. A. Agakhanov, and L. A. Pautov
TURANITE, Cu2+ 5 (V5+O4)2 (OH)4, FROM THE TYUYA MUYUN RADIUM URANIUM DEPOSIT, OSH DISTRICT, KYRGYZSTAN: A NEW STRUCTURE FOR AN OLD MINERAL
Can Mineral, June 1, 2004; 42(3): 731 - 739.
[Abstract] [Full Text] [PDF]

Home page
 American MineralogistHome page
B. Lanson, V. A. Drits, A.-C. Gaillot, E. Silvester, A. Plancon, and A. Manceau
Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction
American Mineralogist, November 1, 2002; 87(11-12): 1631 - 1645.
[Abstract] [Full Text] [PDF]

Home page
 Can MineralHome page
F. C. Hawthorne and E. Sokolova
SIMONKOLLEITE, Zn5 (OH)8 Cl2 (H2O), A DECORATED INTERRUPTED-SHEET STRUCTURE OF THE FORM [M{phi}2]4
Can Mineral, June 1, 2002; 40(3): 939 - 946.
[Abstract] [Full Text] [PDF]

Home page
 Can MineralHome page
F. C. Hawthorne and M. Schindler
TOPOLOGICAL ENUMERATION OF DECORATED [Cu2+{phi}2]N SHEETS IN HYDROXY-HYDRATED COPPER-OXYSALT MINERALS
Can Mineral, June 1, 2000; 38(3): 751 - 761.
[Abstract] [Full Text] [PDF]


JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Mineralogical Society of America