Redox

Redox (short for reduction–oxidation reaction) is a chemical reaction in which the oxidation states of atoms are changed. Redox reactions include all chemical reactions in which atoms have their oxidation state changed.

General aspects

Redox reactions involve the transfer of electrons between chemical species. The chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. It can be explained in simple terms:

• Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
• Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.

Important reactions

Oxidation

• Acyloin condensation
• Adkins–Peterson reaction
• Collins oxidation
• Corey–Kim oxidation
• Dakin oxidation
• Dess–Martin oxidation
• Fleming–Tamao oxidation
• Jones oxidation
• Lindgren oxidation
• Oppenauer oxidation
• Pinnick oxidation
• Sarett oxidation
• Swern oxidation

Reduction

• Bechamp reduction
• Benkeser reaction
• Birch reduction
• Bosch reaction
• Bouveault–Blanc reduction
• Carbonyl reduction
• Clemmensen reduction
• Corey–Itsuno reduction
• Emde degradation
• HI/P reduction
• Hydrogenation
• Rosenmund reduction
• Mozingo reduction
• Wolff–Kishner reduction
• Zinin reaction

Reagents used

Oxidizing agents

• Free elements: oxygen, fluorine, chlorine, bromine, iodine.
• Interhalogens: bromine monochloride, bromine pentafluoride, bromine trifluoride, chlorine trifluoride;
• Covalent halides: oxygen difluoride, sulfuryl chloride, phosphorus pentabromide, PTFE (very high temperatures only)
• Nonmetal oxides: dinitrogen pentoxide, nitrous oxide, nitrogen dioxide, ozone, sulfur trioxide, chlorine oxides, bromine oxides, iodine oxides, xenon oxides;
• Metal oxides: bismuth trioxide, chromium trioxide, osmium tetroxide, sodium superoxide;
• Peroxides: barium peroxide, hydrogen peroxide, vanadium pentoxide, zinc peroxide;
• Acids: chloric acid, chromic acids, nitric acid, peracids, perchloric acid, periodic acid, peroxydisulfuric acid, peroxymonosulfuric acid;
• Salts: bismuthates, chlorates, chlorites, chromates, dichromates, ferrates, hypochlorites, iodates, manganates, nitrates, nitrites, perborates, perchlorates, periodates, permanganates, persulfates, perxenates, tetrafluoroborates;
• Mixtures: aqua regia, nitrating mixture, piranha solution;
• Miscellaneous: bromine water, Fenton's reagent, Frémy's salt, lead(IV) acetate

Reducing agents

• Free elements: carbon, hydrogen, magnesium
• Metal hydrides: calcium hydride, lithium aluminium hydride, sodium borohydride
• Nonmetal hydrides: hydrazine, phosphine
• Acids: ascorbic acid, citric acid, formic acid, hydrogen sulfide, hydroiodic acid
• Salts: metabisulfites, sulfites, thiosulfates
• Sugars: fructose, glucose
• Oxides: carbon monoxide, nitric oxide, sulfur dioxide
• Alloys: Devarda's alloy, Raney nickel, Na-Pb
• Amalgams: Zn-Hg, Na-Hg, Al-Hg
• Salts: low oxidation state salts
• Miscellaneous: palladium on carbon

References

Relevant Sciencemadness threads

• Handling Redox Equations