I believe both terms to be very similar if not interchangable. From the Glossary of Chemical Priciples by Masterton and Slowinski. Oxidation number a number which can be assigne to an atom in a molecule or ion which reflects ,qualitatively, it's state of oxidation. Examples in the N03- ion the N and O atoms are +5 and -2 respectively.
From a Book The Elements by John Emsley gives the same information of N03 but uses the term Oxidation state.
Oxidation No. of an element in a chemical species (e.g. atom, molecule, ion etc) , may be regarded as the average charge acquired by an atom of that element, if the species is considered to be an aggregate of ions. Oxidation state of a particular atom of an element in a chemical species may be regarded as the charge acquired by that particular atom , if the species is considered to be an aggregate of ions.
The oxidation No. of carbon in propane is -8/3 where as the oxidation states of both carbon atoms at extremities are -3 and that of the middle one is -2. Hence the average is -8/3 I like to know whether Mr Peteeo agree with me or not
This message has been edited. Last edited by: dk_ch,
I saw your additional post and have pondered how to answer in a coherent fashion with some support from literature better than I.
From one of my instructor’s ‘All models are wrong (imperfect). Some are better than others. Strive to use the simplest model that helps you solve your problem’. I like the definitions you’ve given and they have a subtle difference between them. Using the molecule propane and the statement ‘if the species is considered to be an aggregate of ions’, your explanation of the charges on the due to the hydrogen ions would be logical. To satisfy the octet rule we need to also consider the neighboring carbon atoms as well. The 2 methyl groups each have a shared electron from the central carbon .. making the oxidation state -IV. Similarly at a random instant of time the central carbon methylene group has the electrons from the carbons of the methyl group to fill it’s octet giving it a -IV charge too. Another instant of time each one of the carbons could have given up the electons to it’s neighbors and be in the +IV stated. On a grand average over a period of time they’d each be pretty neutral. Concurrently the hydrogen is flipping from +I to –I oxidation numbers and states.
Quoting from John Emsley’s book The Elements. Carbon has 4 oxidation states allows +IV +II 0 -IV with the examples of C02, C0, C, CH4 given in the same sequence. There was also a statement ‘Oxidation states’ ‘ This concept is rarely used in discussing carbon and it’s compounds because of their subtleties of bonding. However, for simple compounds with a single carbon we can use it. ‘ He also gives a couple more examples of +IV carbon compounds of C03= and CF4.
Most books tend to treat carbon participating in covalent bond models vs ionic. At small instants of time the Ionic model will present one state and the next instant a different state but over a long period of time the net average is zero. This would be the definition of a covalent bond. If we look at the electronegativities of oxygen or fluorine the odds shift to be more ionic in nature to tune the model etc.
I hope this has not caused more confusion. I’ll post this to the forum as well. Peteeo
