symmetry-forbidden reactions

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• Symmetry — For other uses, see Symmetry (disambiguation) …   Wikipedia

• symmetry — /sim i tree/, n., pl. symmetries. 1. the correspondence in size, form, and arrangement of parts on opposite sides of a plane, line, or point; regularity of form or arrangement in terms of like, reciprocal, or corresponding parts. 2. the proper or …   Universalium

• Theoretical astronomy — Nucleosynthesis Stellar nucleosynthesis Big Bang nucleosynthesis Supernova nucleosynthesis Cosmic ray spallation …   Wikipedia

• Astrochemistry — is the study of the chemical elements found in outer space, generally on larger scales than the Solar System, particularly in molecular gas clouds, and the study of their formation, interaction and destruction. As such, it represents an overlap… …   Wikipedia

• Möbius–Hückel concept — The Möbius Hückel treatment is one of two predicting reaction allowedness versus forbiddeness. The concept is the counterpart of the Woodward Hoffmann approach. The methodology in this treatment utilizes the plus minus sign parity in proceeding… …   Wikipedia

• Woodward–Hoffmann rules — The Woodward–Hoffmann rules devised by Robert Burns Woodward and Roald Hoffmann are a set of rules in organic chemistry predicting the stereochemistry of pericyclic reactions based on orbital symmetry. These include electrocyclic reactions,… …   Wikipedia

• Olefin metathesis — or transalkylidenation is an organic reaction that entails redistribution of alkylene fragments by the scission of carbon carbon double bonds in olefins (alkenes).[1] Its advantages include the creation of fewer sideproducts and hazardous wastes …   Wikipedia

• Charge transfer complex — A charge transfer complex (or CT complex, electron donor acceptor complex) is a chemical association of two or more molecules, or of different parts of one very large molecule, in which the attraction between the molecules (or parts) is created… …   Wikipedia

• Charge-transfer complex — A charge transfer complex (CT complex) or electron donor acceptor complex is an association of two or more molecules, or of different parts of one very large molecule, in which a fraction of electronic charge is transferred between the molecular… …   Wikipedia

• Alkyne trimerisation — An alkyne trimerisation reaction is a 2+2+2 cyclization reaction in which three alkyne molecules react to form an aromatic compound. The reaction is pseudo pericyclic since it has not been observed to occur without the assistance of metal… …   Wikipedia

• Mass-independent fractionation — Mass independent (isotope) fractionation refers to any chemical or physical process that acts to separate isotopes, where the amount of separation does not scale in proportion with the difference in the masses of the isotopes. Most isotopic… …   Wikipedia