Unknowns in the chemistry of boron

Jemmis, Eluvathingal D and Prasad, Dasari LVK (2008) Unknowns in the chemistry of boron. In: Current Science, 95 (9). pp. 1277-1283.

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Abstract

Structural links between benzenoid aromatics and graphite as well as saturated hydrocarbons and diamond are seen in high school text books. A similar understanding is only beginning to emerge in the chemistry of boron. Unlike benzenoid aromatics where the condensation is usually by edge-sharing, there are several ways of condensing polyhedral boranes. These include edge-sharing, triangular face sharing, four atom sharing and a single atom sharing. An electron counting mno rule similar to the Huckel 4n + 2 pi electron counting rule will be presented for mono and condensed polyhedral boranes. Application of this rule shows that the structural details of beta-rhombohedral boron, such as the vacancies and extra occupancies in the unit cell are a consequence of the electronic requirements rather than defects in the structure. While this is the beginning of a general understanding, there is a long way to go before the quantitative details emerge in this area, along with the synthesis and chemistry of a variety of condensed boranes. These ideas also provide a relationship between boron and fullerenes. Further, designing stable boron-rich candidates for physiological applications and materials for use in extreme conditions are areas that are waiting to be explored.

Item Type:	Journal Article
Additional Information:	Copyright of this article belongs to Indian Acadamy Of Sciences.
Keywords:	Benzoid aromatics;elemental boron;macropolyhedral boranes;mno electron counting rule.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	24 Mar 2009 09:46
Last Modified:	19 Sep 2010 04:58
URI:	http://eprints.iisc.ernet.in/id/eprint/17686

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