An electrocyclic reaction is a pericyclic reaction involving the net loss of a pi bond and creation of a sigma bond with formation of a ring.
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The cyclic oligomers form when the nitrogen of the amide forms a sigma bond to a lithium while the nitrogen lone pair binds to another metal centre.
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The thiyl radical propagates with the alkene to form a carbon centered radical, the previous double bond now allows free-rotation around the sigma bond.
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It was first reported in 1848 from the reaction of zinc and ethyl iodide, and was the first compound known to contain a metal carbon sigma bond.
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This is contrasted by sigma bonds which form bonding orbitals directly between the nuclei of the bonding atoms, resulting in greater overlap and a strong sigma bond.
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This is contrasted by sigma bonds which form bonding orbitals directly between the nuclei of the bonding atoms, resulting in greater overlap and a strong sigma bond.
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A typical triple bond, for example in acetylene, consists of one sigma bond and two pi bonds in two mutually perpendicular planes containing the bond axis.
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Molecules with rings have additional sigma bonds, such as benzene rings, which have 6 C " C sigma bonds within the ring for 6 carbon atoms.
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Molecules with rings have additional sigma bonds, such as benzene rings, which have 6 C " C sigma bonds within the ring for 6 carbon atoms.
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In coordination complexes, only the first or sigma bond between each ligand and the central atom counts, but not any pi bonds to the same ligands.
