oxidation Chem.
(ɒksɪˈdeɪʃən)
Also oxy-.
[a. F. oxidation (G. de Morveau and Lavoisier, 1787; oxydation in Dict. Acad. 1835), n. of action from oxider: see prec.]
1. a. The action or process of oxidating; combination with oxygen; conversion into an oxide or oxygen-compound. Also, the removal of hydrogen from a compound.
| 1791 Hamilton Berthollet's Dyeing I. i. i. i. 10 The regular succession of colours in iron, according to its degree of oxydation (calcination). 1816 J. Smith Panorama Sc. & Art II. 301 Oxidation, or oxygenation, or oxidizement, the combination of any other body with oxygen. 1862 Dana Man. Geol. §52. 51 The processes of oxydation and deoxydation..give a degree of activity even to the world of rocks. 1866 [see dehydrogenation]. 1871 Roscoe Elem. Chem. 13 In this act of combination, which is termed oxidation, heat is always, and light is frequently given off. 1885 G. L. Goodale Physiol. Bot. (1892) 355 The reception of oxygen, the oxidation of the oxidizable matter..etc...are collectively called respiration. 1900 Jrnl. Chem. Soc. LXXVIII. i. 301 (heading) Oxidation of the nature of dehydrogenation by means of ferricyanides. 1959 Cram & Hammond Org. Chem. vi. 73 In organic chemistry, oxidation involves the removal of hydrogen and (or) the addition of oxygen or some other hetero atom to a compound. |
| attrib. 1839 Ure Dict. Arts 1162 [He] scrapes its entire surface clean and free from oxidation-scale or fire-strain. |
b. In extended use: the partial or complete removal of an electron from an atom or molecule; an increase in the proportion of electronegative constituents in a molecule or compound.
| 1892 Morley & Muir Watts' Dict. Chem. III. 657 The term oxidation has been widened until at present it is applied to all chemical changes which result in an addition of a negative radicle, simple or compound, to elements or compounds, or a decrease in the relative quantity of the positive radicle of a compound, whether this is or is not accompanied by substitution of a negative radicle..e.g. the following change: 4Fe + 3O2 = 2Fe2O3. 1907 Whitney & Brown tr. Le Blanc's Text-bk. Electro-Chem. vii. 256 There must be, in every galvanic cell, an oxidation at one electrode and a reduction at the other. 1928 H. L. Hind tr. Schoen's Probl. Fermentation xiv. 167 There is a change from divalent iron to iron at a higher degree of oxidation. 1968 Passmore & Robson Compan. Med. Stud. I. viii. 5/2 It is also characteristic of biological oxidations that they are often linked together to form a chain along which the electrons flow. |
2. Special combs.:
oxidation number, the charge (expressed in units of the negative of the electron charge) which is assigned to an atom on the assumption that the bonding in the substance or radical in which it exists is completely ionic; the average formal charge so assigned to atoms of a particular element in a compound or radical;
oxidation potential, the electrode potential required to bring about a particular oxidation reaction at the electrode;
oxidation-reduction = redox;
freq. attrib.;
oxidation state, oxidation number; the state of having a particular oxidation number.
| 1948 Jrnl. Chem. Educ. XXV. 278/2 The O2 molecule..is made up of two neutral atoms..; the oxidation number of the O atom is consequently zero. 1964 Cram & Hammond Org. Chem. (ed. 2) vi. 98 The system described is similar to the inorganic system if effective oxidation numbers, ranging from -4 (in CH4) to +4 (CCl4 or CO2), are assigned to individual carbon atoms within organic molecules. 1968 J. March Adv. Org. Chem. xix. 853 Carbon in propane has an oxidation number of -2·67 and in butane of -2·5, though organic chemists seldom think of these two compounds as being in different oxidation states. |
| 1900 Jrnl. Chem. Soc. LXXVIII. ii. 642 An attempt was made to measure a number of oxidation potentials. 1942 C. E. K. Mees Theory Photogr. Process viii. 308 When a silver salt solution is added to a reducing solution, there is an adjustment of the oxidation potentials of each to a common value intermediate between the two. 1966 C. R. Tottle Sci. Engin. Materials x. 225 The readiness to ionize by losing electrons in the presence of an ionizing solvent is called the oxidation potential. |
| 1909 Chem. Abstr. III. 2648 It is therefore unnecessary to assume..that the e.m.f. in an oxidation-reduction cell is due to H2 or O2 at definite pressure in the electrode. 1951 New Biol. XI. 29 The over-all reaction in photosynthesis is of a type, extremely important in living organisms, known as an oxidation-reduction, in which one compound becomes oxidized at the expense of another which is reduced. 1974 Sci. Amer. Dec. 65/2 Chemical processes of this kind, in which electrons are transferred from one molecule to another, are called oxidation-reduction reactions. 1975 Jrnl. Biol. Chem. CCL. 3929 The oxidation-reduction equilibrium of the γ chains of human fetal hemoglobin. |
| 1942 Sneed & Maynard Gen. Inorg. Chem. vi. 120 In many cases an element in its oxide or chloride is not reduced to the free state [by hydrogen] but to a lower oxidation state. 1973 J. G. Dick Analytical Chem. ii. 15 The hydrogen atom is assigned an oxidation state of + 1, except in hydrides where the oxidation state is generally -1. |