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Co-ordination of boron in sillimanite

Grew, Edward S. and Rossman, George R. (1985) Co-ordination of boron in sillimanite. Mineralogical Magazine, 49 (350). pp. 132-135. ISSN 0026-461X. doi:10.1180/minmag.1985.049.350.20.

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Ion-Microprobe analyses of six sillimanites associated with kornerupine show that the sillimanite can incorporate from 0.035 to 0.43 wt. % B_2O_3 (Grew and Hinthorne, 1983). Boron appears to substitute for silicon concomitantly with Mg substitution for Al such that the atomic Mg/B ratio is close to 0.5. This substitution results in a deficiency of cationic charge, which Grew and Hinthorne (1983) attributed to a submicroscopic rearrangement of the sillimanite structure involving loss of oxygen. A possible substitution scheme is 2(B + xMg) → 2(Si + xAl) + (1 + x)O, where x ≃ 0.5. In the present study, we have addressed the question of co-ordination of boron in sillimanite. As boron can occur in trigonal or tetrahedral coordination with oxygen, there is no compelling reason that B substitution for Si implies tetrahedral co-ordination for B.

Item Type:Article
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Rossman, George R.0000-0002-4571-6884
Additional Information:© 1985 The Mineralogical Society. Manuscript received 17 April 1984; revised 2 August 1984. We thank R.I. Gait for sample E 2724 from the collection of the Royal Ontario Museum, Toronto; K. Abraham (Bochum) and N. Marquez (Aerospace Corporation, Los Angeles) for assistance with the electron and ion microprobe analyses; G. Mathe and J. Hofmann (Freiberg) for guidance to the Waldheim locality, M.A. Carpenter (Cambridge) for the TEM work, and W. Schreyer (Bochum) for comments. Grew's research at Bochum was supported by the Alexander von Humboldt-Stiftung (Bonn) and Rossman's research in part by US National Science Foundation Grant EAR-79-19987.
Funding AgencyGrant Number
NSFEAR 79-19987
Subject Keywords:ion microprobe, boron, sillimanite
Non-Subject Keywords:ion microprobe; boron; sillimanite
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Caltech Division of Geological and Planetary Sciences 4702
Issue or Number:350
Record Number:CaltechAUTHORS:20140305-135909102
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Official Citation:Grew, E. S., & Rossman, G. R. (1985). Co-ordination of boron in sillimanite. Mineralogical Magazine, 49, Part 1(350), 132-135. Retrieved from
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44161
Deposited By: Ruth Sustaita
Deposited On:05 Mar 2014 22:48
Last Modified:10 Nov 2021 16:48

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