| Autor: |
Dirken, Peter J., Kentgens, Arno P. M., Nachtegaal, Gerda H., Eerden, M. J. van der, H. Jansen, J. Ben |
| Zdroj: |
American Mineralogist (De Gruyter); January 1995, Vol. 80 Issue: 1-2 p39-45, 7p |
| Abstrakt: |
The minerals zunyite, Al13Si5O20(OH9F)18Q5and harkerite, Ca24Mgg[AlSi4(O5OH) 16]2- (CO3)8(BO3)8(H2O9Q)5have been studied by means of solid-state 27Al MAS NMR. Zunyite contains Si5O16pentamers and harkerite contains AlSi4(O5OH)16pentamers. These pen- tameric groups are unique because their T-O-Si angles are almost 180°. Chemical analysis of the zunyite sample shows that it has excess Al: the Al-Si ratio is 2.9, compared with the ideal of 2.6. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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