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In chemistry, bond cleavage, or bond fission, is the splitting of chemical bonds. This can be generally referred to as dissociation when a molecule is cleaved into two or more fragments.[1]
In general, there are two classifications for bond cleavage: homolytic and heterolytic, depending on the nature of the process. The triplet and singlet excitation energies of a sigma bond can be used to determine if a bond will follow the homolytic or heterolytic pathway.[2] A metal−metal sigma bond is an exception because the bond's excitation energy is extremely high, thus cannot be used for observation purposes.[2]
In some cases, bond cleavage requires catalysts. Due to the high bond-dissociation energy of C−H bonds, around 100 kcal/mol (420 kJ/mol), a large amount of energy is required to cleave the hydrogen atom from the carbon and bond a different atom to the carbon.[3]
- ^ Muller, P. (1 January 1994). "Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)". Pure and Applied Chemistry. 66 (5): 1077–1184. doi:10.1351/pac199466051077. S2CID 195819485.
- ^ a b Michl, Josef (May 1990). "Relationship of bonding to electronic spectra". Accounts of Chemical Research. 23 (5): 127–128. doi:10.1021/ar00173a001.
- ^ Wencel-Delord, Joanna; Colobert, Françoise (2017). "Super-reactive catalyst for bond cleavage". Nature. 551 (7681): 447–448. Bibcode:2017Natur.551..447.. doi:10.1038/d41586-017-07270-0. PMID 29168816.