| 11. | In this case there are 16 C " C sigma bonds and 10 C " H bonds.
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| 12. | The inductive effect drops across every sigma bond involved limiting its effect to only a few bonds.
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| 13. | Anchimeric assistance of the sigma bond between carbons 1 and 6 was rationalized as the explanation for this kinetic effect.
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| 14. | For there to be a constructive sigma bond formed after the shift, the reaction would have to be suprafacial.
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| 15. | In these compounds the central bond consists only of pi bonding because of a sigma antibond accompanying the sigma bond itself.
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| 16. | Silicon can form sigma bonds to other silicon atoms ( and disilane is the parent of this class of compounds ).
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| 17. | In the second step, the nucleophilic reagent ( Nuc : ) attaches to the carbocation and forms a covalent sigma bond.
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| 18. | Each silicon of the double bond uses its three " sp 2 " hybrid orbitals to form sigma bonds to three atoms.
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| 19. | Another difference is that the barrelene reaction requires the intersystem-crossing ( ISC ) to provide paired electrons and a new sigma bond.
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| 20. | A pi bond is generally weaker than a sigma bond, so easier for an electrophile ( aka lewis acid ) to go after.
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