Wades rules for structural elucidation of boranes and. In chemistry the polyhedral skeletal electron pair theory psept provides electron counting rules useful for predicting the structures of clusters such as borane. The isolobal principle and application of wade s rules last updated. The isolobal principle and application of wades rules. Ken wade developed a method for the prediction of shapes of borane clusters. To use this method, the total number of valence electrons that are forming the bonds must be determined n number of boron atoms. Boranes boranes are compounds composed solely of boron and. Boranes assigning closo, nido, arachno, hypo nomenclature. The type of structure adopted by a particular compound has been shown to related to the number of electrons that are available in the compound for bonding within the polyhedral framework. Polyhedral skeletal electron pair theory wikipedia. The structure of the numerous boranes and carboranes falls into the closo nido and arachno categories.
Boranes is the name given to the class of synthetic hydrides of boron with generic formula b x h y. The wade rules are a correlation between the number of electrons, the formula and the shape of the molecule. In the past, borane molecules were often labeled electrondeficient because of their multicenter bonding in which a pair of bonding electrons links more than two atoms, as in 3center2electron bonds. The jemmis mno rule provides the relationship between polyhedral boranes, condensed. A second method to determine the geometry of boranes are the wade rules. In chemistry, the jemmis mno rules represent a unified rule for predicting and systematizing. A way of correlating the number of framework electrons with the structure is by wade rules and it proposed. Wades rules though the lipscombs topological model involving styx numbers and rules was good in the rationalization of structures of some of the boranes and related species, it was not enough to higher boranes and carbonyl clusters. Wades rules are used to rationalize the shape of borane clusters by calculating the total number of skeletal electron pairs sep available for. The chemistry of the boranes was first studied systematically by alfred stock. Wade s rules tlv february 11, 2019 bonding in the polyhedral boranes wade s rules since alfred stocks early preparation of the boron hydrides, b x h y, these molecules have played an important role in understanding covalent bonding. Therefore, a more sophisticated and comprehensive method was needed.
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