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Previously the article said that a large electronegativity difference results in ionic bonding, 0.2 - 1 polar, and below 0.2 non-polar. My chemistry book says >=2.0 forms an ionic bond, 0.4 - 2.0 polar covalent, and <=0.4 nonpolar covalent. Note that I'm using the Pauling scale. The electronegativity scale was not specified, so I changed the values.

Jeff Connelly 01:10 28 May 2003 (UTC)

I thought that ionic was over 1.7. -Smack 01:56 9 Jul 2003 (UTC)
Actually, EN difference alone does not, strictly, determine the ionic/covalent nature, for example, solid LiH, delta EN = 1.1, is ionic, whereas SiF4, delta EN = 2.1, is covalent!
Furthermore, the whole scale is a continuum. It's not like when you go from 1.9 to 2.1 all of a sudden the bonds have completely changed. Olin 14:31, 3 March 2006 (UTC)

Someone should say something about the elements that do not have electronegativities (i.e. the actinides and noble gases). -Smack 01:56 9 Jul 2003 (UTC)

The article says Francium has the least electronegativity then it says Caesium does. I know electronegativities increase across periods and decrease down groups but I want to know what the exceptions are and why this article has contradicted itself?

In theory, francium would be the least electronegative. However, due to all its isotopes' extreme radioactivity and rapid decay, it could never be feasibly experimented with or observed. For this reason, caesium is usually referred to as the "least" or "most" (e.g., most reactive in group I, least electronegative, etc.) in cases where francium deserves that title. Maybe this should be mentioned in the article?
Doshea3 10:17, 29 May 2005 (UTC)
Fr does not deserve that title. Cs is more electronegative, due to relativistic effects. See alkali metal and francium for a more thorough look at it. Double sharp (talk) 04:29, 14 September 2013 (UTC)

Could someone add a word about chemical potential?[edit]

I would love to see a few words relating electronegativity to the chemical potential. —Preceding unsigned comment added by (talk) 22:09, 7 November 2007 (UTC)

Yes, electronegativity should be a potential which correlates the energy or force with respect to its environmental distance. Yonghe Zhang proposed a new finding [1] : everything exists in Ionocovalent potential that the ionic energy harmonized with the covalent environment. It correlates with quantum potential and spectroscopy [2]:

I(Z*)(n*rc-1) = Ze2/r = n*(Iz/R)½ rc-1

The ionocovalent potential (IC) and its derivers IC-electronegativities have much more versatile and exceptional applications than the traditional electronegativity scales.

[1] Science Letter, February 22, 2011

[2] Zhang, Y. Int. J. Mol. Sci. 2010, 11, 4381-4406.

Thank you! Fenhmm (talk) 22:47, 17 November 2013 (UTC)

plagiarism somewhere[edit]

See - this seems to be word-for-word the same as the Wiki article. Who copied from whom? Cbdorsett 10:58, 23 Mar 2005 (UTC)

- An entry has been added to the linked above website noting the source as Wikipedia.

They are a mirror of us. — Omegatron 15:10, 6 December 2005 (UTC)


I removed:

Electronegativity is a measure of the attraction that an atom has for the bonding pair of electrons in a covalent bond.

Replaced with:

Electronegativity is the ability of an atom or a molecule to attract shared electrons to itself.

This latter is a far more general, certainly more accurate definition. Electronegativity is a trait considered not only in covalent compounds, but in Ionic and polar covalent as well.

So I see someone reverted my edit without even a discussion? The current definition is even more incorrect than it was...reverting edit of ""
  • I'm afraid I am confused as to the definition of this word. Surely, although related, the ability of an atom to attract electrons and form anions is quantitively different to the attraction an atom may have to attract electrons in an already existing covalent bond? Obviously there is a strong positive correlation between the two, but they seem quite distinct to me. --postglock

Origin of the Pauling Scale?[edit]

Does anyone know how the intermediate values of the Pauling scale were assigned? The current article sidesteps the issue. On the first read through, I got the impression the values were assigned relative to Fluorine & Francium, but on careful review, this doesn't seem to be the case. (At anyrate, it ignores how each atom was interpolated, anyway.) 23:02, 8 Jun 2005 (UTC)

Addendum: The body of the article says Fluorine is assigned as 4.0, but the table gives a value of 3.98 - 23:07, 8 Jun 2005 (UTC)

If X_a is the elektronegativity of element a en X_b that of element b then X_a-X_b=sqrt(delta/23) with D(AB)=sqrt(D(A_2)*D(B_2))+delta and D(...) the dissociation energy of the molecule.. That's how i learned it..

Accuracy Disputed Tag[edit]

I've added an accuracy disputed tag, because the initial definition is not precise and probably incorrect. It seems to me that the energy involved in creating anions is probably the incorrect meaning here, and the correct meaning is to do with the attraction in existing covalent bonds. The energy involved in creating a -1 ion appears to be called electron_affinity, and so I would assume that this is a distinct and separate meaning. If anyone could clear this up, it would be appreciated. -- postglock 4 July 2005 08:45 (UTC)

Maybe I can help clear this up. Simply put, Electronegativity is the ability of an atom to attract electrons. Period. An atom's ability to attract electrons is not affected by any bonds that it is in. Rather, both atoms are pulling with their respective Electronegativities, and the type of bond formed is the result of this tug-of-war. I think the opening of this article should read "Electronegativity is the measure of the ability of an atom or molecule to attract electrons. The type of bond formed is determined by the difference in Electronegativity between the two atoms. Atoms with similar Electronegativities will constantly 'steal' an electron from each other (commonly referred to as 'sharing') and form a covalent bond. However, if the difference is too great, the electron will be permanently transferred to one atom and an ionic bond will form. Furthermore, if one atom pulls slightly harder than the other, a polar covalent bond will form." Now here's where the different scales come in. Also, the specific values for each kind of bond should be removed from the trends section and put in their respective scale sections. That information has nothing to do with periodic trends. Also, the rounded figures need to go, and the whole Mulliken scale needs some serious help. Given the stamp of approval, I'd be glad to do all these things.the1physicist 9 July 2005 04:37 (UTC)
I hereby give you my stamp of approval, as an official Chemistry and Physics teacher. I think that's as official as it gets on the Wikipedia, right? RobertAustin 00:52, 19 October 2006 (UTC)

I think I may be partly confused about the differences concerning bonds. I have read that chemical bonds range from ionic to polar covalent to non-polar covalent, but I've never totally understood this. Obviously the degree of polarity may be a continuous range, but surely there are distinct differences between covalent and ionic bonds per se? (i.e. by simply counting whether electrons are shared or borrowed to fill shells) Regardless, surely in terms of the different scales, these have been empirically produced from some consistent procedure? (e.g. change in energy when adding an electron? or level of polarity in covalent bonds?)

In any case, if you feel that you can improve this article, you should be bold in updating pages! Go for it!

--postglock 07:28, 13 July 2005 (UTC)

The degree of polarity is indeed a continuous range. There are not really 'distinct' differences between closely separated bonds types. (That is, a 1.4 bond behaves similarly to a 1.5, etc.) In terms of an exact numerical cutoff for each bond type, that doesn't really exist. You will find slightly different numbers in different books. I noticed updated the article with an interesting example, so allow me to point out his error. True, the bond between Si and F *should* be ionic, but that same Silicon atom is being shared with 4 Fluorine atoms. Because of this, the pull of the Silicon atom is essentially reduced by a factor of 4, and hence, it is covalent. I could go into much further detail, but it would be much too complicated and this is not the place. More importantly, I think it confuses things more than it adds clarity, so I would be in favor of removing it. I guess I'll make some edits and see what happens.the1physicist 21:56, 13 July 2005 (UTC)

The reason I had added the LiH / SiF4 examples is to demonstrate something. You see, whether a compound is ionic or covalent is determined not by electronegativity difference, but rather by whether the lattice energy is enough to compensate for the energy required for ion formation. Solid LiH is an ionic compound because the energy required to form Li+ and H- ions is compensated for by the lattice energy of combination of such ions. On the contrary, the formation of Si4+ and F- ions is unfavorable because the charge density of Si4+ would be extremely high. Therefore, SiF4 is covalent, even though its E.N. difference is nearly twice that of ionic LiH. My whole point, I shall repeat, is that whether a compound is ionic or covalent is determined not by electronegativity difference, but rather by whether the lattice energy is enough to compensate for the energy required for ion formation. I feel that it's too much of a misconception.
You basically have to ask yourself what is lattice energy? And the (overly) simplified answer is that lattice energy is just a nice number that lets us do equations easier. The important thing to remember here is that lattice energy is determined by the forces between the atoms and electrons. Hence, we're talking about one and the same thing, so I see no need to obfuscate the matter (pun intended).the1physicist 04:19, 15 July 2005 (UTC)

For those who like it simple, DO NOT READ BEYOND THIS POINT! The whole concept that each element can be assigned a single value that defines how it attracts electrons is by far an over-simplification. Even the same two elements can form different types of compounds. MnO is an ionic compound, but Mn2O7 is covalent! It just isn't right to say that the electron-drawing ability of an atom of a particular element is a constant. It depends on the circumstances. It is simply wrong that atoms of a particular element always have the same potential to draw bonding electrons toward themselves!

I believe it may be time to move this sub-discussion to another page.

Diamond is electronegative?[edit]

The article here says that diamond is highly electronegative. Could someone confirm and then add it to the article? It would be useful to go into why diamond being electronegative would be a useful property. --ShaunMacPherson 02:08, 13 September 2005 (UTC)

It wets steel... It's sabotaged by H2. It really wants to bond with something else, if you know what I mean. Diamonds aren't forever.lysdexia 04:08, 6 November 2005 (UTC)

[C-C bonds are pretty strong compared with many other group 14's. The article is "popular" science, it is not the most brilliant description, basically it refers to nano-tubes of diamond, and mentions an electronegative surface - but this still brings you back to treating the surface C you want to bond something to as just a generic carbon. I would argue that this article is probably pretty "specialist", and that for this article is not very relevant in itself.]


Atoms with similar electronegativities will constantly 'steal' an electron from each other (often misleadingly referred to as 'sharing')

Uh... how is that more misleading than saying they "steal"? — Omegatron 15:09, 6 December 2005 (UTC)

[Technically they do share electron density - there is no more appropriate simple word. They "require" electrons and thus "share" them, to steal electrons does suggest more of an active conscious mode of going about this, when in reality the electron orbitals will be distorted by localised charge interactions. In some way you could say steal, but only if you subscribe to primitive methods of viewing electrons, as it would suggest you could at any one time say that one of the pair of atoms in a diatomic "owned" the electron at that moment, before the other atom takes it. This is impossible thanks to that nice man with his uncertainty principle. Thus even in models of "full" ionic systems modeled using DFT techniques etc. even though the ionic nature is explicitly shown you have to say that there are regions of electron denisty that are effectively zero.]


What do u mean by 'Atoms with similar electronegativities will constantly 'steal' an electron from each other (often misleadingly referred to as 'sharing') and form a covalent bond.' Isn't it called as sharing?

I believe that was a typo. Unless I'm mistaken, it should read "and form an ionic bond." Then again, I failed Chemistry my fourth term..


a simple electrolysis example needs to be included. not only is this the place people often come across electronegativity, a neat example would also give a lot of people a clear picture of what this article is on about

Effective Nuclear Charge[edit]

This article would benefit from a discussion of effective nuclear charge and how it determines electronegativity. I'm no chemist, so I hesitate to write it myself. Expert needed.JohnJohn 01:40, 29 August 2006 (UTC)

You have a good idea. Pauling and Allred-Rochow originally defined electronegativity as “the power of an atom in a molecule to attract electrons”. However they actually did not take account the different valence states even though the attraction of the atom to electrons is decided by the environment of the atom in the molecule. The higher the charge number of an element in a compound, the more strongly its atom attracts electrons. Using this approach we have more physically defined the electronegativity of the element in valence states as the electrostatic force exerted by the effective nuclear charges on the valence electrons.

In 1981-1982, on the basis of Bohr energy model,

                             E = - Z2me4/8n2h2ɛ02 = - RZ2/n2

Yonghe Zhang proposed the effective principal quantum number n* and the effective quantum nuclear charge Z* from the ionization energy [1,2]:


And the first scale of electronegativity in different valence states on spectroscopy corresponding quantum electron configurations of the orbital from 1s to nf was proposed [1,2]:

                          Xz = 0.241 n*( Iz /R) ½rc-2 + 0.775

Then the ionocovalent potential (IC) and its derivers IC-electronegativity XIC have been proposed [3]:

                                  IC = n*(Iav/R)½ rc-1
                          XIC =0.412 n*(Iav/R)½ rc-1 + 0.387

which have much more versatile and exceptional applications than the traditional electronegativity scales [3].

[1] Y. Zhang, J. Molecular Science, (Chinese) 1 (1981) 125.

[2] Y. Zhang, Inorg Chem. 21 (1982) 3886.

[3] Zhang, Y. Int. J. Mol. Sci. 2010, 11, 4381-4406.

Thank you! Fenhmm (talk) 01:12, 18 November 2013 (UTC)


I must say, this article is very confusing for people who don't know what covalency and all that stuff is. I thought Electronegativity was how well something conducted electricity. Caesium is supposed to be a really good insulator, right?Madking 14:29, 3 March 2007 (UTC)

Those terms used in the article here, such as "covalent bond", are wiki-linked so you can learn exactly what they mean. Caesium, being a metal, would be expected to be a good conductor. DMacks 08:40, 5 March 2007 (UTC)

Electronegativity vs Quantum Mechanics (& Critiscisms)[edit]

-- 22:33, 10 March 2007 (UTC) Electronegativity is an approximatation. The concept has only limited value and should not be enshrined as part of the fundamental theory of chemistry. It is useful and therefore should be learned, but, like valence, is not to be taken too literally. It breaks down if you look at it too closely.

[Agreed - I was just thinking that this was missing from discussion & article. This concept is a mathematical model only, of the complex reality - demonstrated in one of the first posts which states that a sigma of >1.7 for M-X doesn't necessarily indicate ionic bonding. As with many chemical concepts it is retained as it provides a good model to work from in most scenarios, but as such remains inherently limited. Realistically this should be mentioned, and some sort of Critiscisms section should note this and preferably reference an appropriate source - I saw something the other day that may be appropriate, dealing with organolithiums.] {Found this: "Whereas nucleophilicity and basicity are the absolutely dominant features of organic derivatives of potassium, cesium and barium, the reactions of lithium, magnesium, and zinc compounds are, in increasing order, triggered by the electrophilicity (Lewis acidity) of the metal" AND "[Organometallics where historically envisioned as M = cation, C = carbanion] ...This primitive description was very helpful when, in the years after the Second World War, G. Wittig and other pioneers began to advertise the rapidly developing branch of organometallic chemistry. Nevertheless the conceptual reduction of real organometallic species [And also, but generally to a lesser degree, the often talked about ionic M-X species] to fictional carbanions is an oversimplification which must lead to misjudgements. In fact, no difference in organometallic reactivity patterns can be rationalized unless the metal and its specific interactions with the accompanying carbon backbone, the surrounding solvent, and the substrate of the reaction, are explicitly taken into account." [Anything in square brackets I added, normal brackets are author's.] Page 9, page 10 respectively of "Organometallics in Synthesis; A Manual" Second edition, Editor: Schlosser (And this is his section), Wiley 2002, ISBN: 0 471 98416 7.

Over a century of history missing![edit]

Pauling didn't invent electronegativity, although he invented the most ubiquitous numerical electronegativity scale. The concept dates from the early 19th century, and a qualitative scale by Berzelius, from 1836, correlates surprisingly well with the Pauling scale. See Jensen, W. B. J. Chem. Educ. 1996, 73, 11-20. --Itub (talk) 08:43, 21 July 2008 (UTC)

Should merge with electropositivity?[edit]

Does anyone think that electropositivity should be merged into this page? Very similar concept, much shorter article, and no need to have two distinct ones. (talk) 21:08, 2 September 2008 (UTC)

Sounds reasonable to me. --Itub (talk) 09:33, 4 September 2008 (UTC)

Sanderson electronegativity for organic compounds[edit]

Very important that Sanderson electronegativity was introduced for inorganic chemistry. Classical Sanderson's method does not distinguish structural differences. Zefirov and others modified the method to calculate Sanderson electronegativity for every atom in organic molecule.--Tim32 (talk) 18:41, 19 November 2008 (UTC)

Connection to List_of_various_electronegativities and Effective Charge[edit]

Using mostly wikipedia data, it is apparent that some values are missing on this related page which is just a list of various electronegativities with little or no commentary. By calculating the Mulliken electronegativities from other data, I see 26 instances where the tabulated value is not the same as the calculated one, and 29 instances where this fills in data. A couple of the 26 look to be typos, and who knows what radius to use with carbon. The difference between calculated and tabulated looks too large for Oxygen, Fluorine and Bromine, and possibly large for Iodine and Indium. A person can calculate the effective nuclear charge for about half the periodic table based on data largely within wikipedia sites. I have never actually used this data before, I just thought it would come in handy for some data mining I was thinking of doing at some point.

Is this data of interest? If so, any preferences on column order and formatting. Fortran (talk) 16:15, 28 September 2009 (UTC)

Value of "effective nuclear charge" depends on used model! It is not "real charge", but it is model only!--Tim32 (talk) 03:27, 15 January 2010 (UTC)

Electronegativity unts[edit]

Has anyone thought about why electronegativity has no units? —Preceding unsigned comment added by (talk) 17:39, 9 November 2009 (UTC)


I have a doubt regarding the symbol for electronegativity. The symbol should be the letter chi. it looks like an X with curvy ends. But in the article it is given the symbol X. Which is correct and can someone please rectify it? —Preceding unsigned comment added by Suryamp (talkcontribs) 04:17, 14 January 2010 (UTC)

There are many papers and books, where for electronegativity by Pauling used "P" symbol, for electronegativity by Sanderson used "S" symbol etc. It is not problem for this article.--Tim32 (talk) 03:20, 15 January 2010 (UTC)

Merger from Electropositivity[edit]

-- Socob (talk) 22:16, 22 September 2010 (UTC)

electron affinity and Mulliken electronegativity[edit]

I do not think that

"...only ...for an element for which the electron affinity is known"

is a proper wording - I think the affinity is not always "known" because it is undefined for many elements -- not each element can form a negatively-charged ion. (This is because binding to an already electrically neutral atom can be only via an interaction that falls off faster than 1/r^2 with the distance, which in quantum mechanics may or may not have a bound state.) Not being an expert, I'm not changing it yet in case someone disagrees. (talk) 00:31, 5 November 2010 (UTC)

Scale for graphic[edit]

The electronegativity graphic at the top is good but it doesn't have a scale. I know that oxygen is very electro negative and electro negativity increases from left to right, but people shouldn't need to know that to understand the graphic. It should have a scale. —Preceding unsigned comment added by (talk) 20:32, 5 January 2011 (UTC)

The color-coded periodic table in the "Electronegativities of the elements" section? The caption-line right below it reads "Periodic table of electronegativity using the Pauling scale". Even for readers that don't know what this scale actually means numerically, right above the table is a note about the trend "→ Electronegativity increases →". If you have any ideas for more clear ways of stating these notes or making them more obvious, we're obviously open to suggestions. DMacks (talk) 21:09, 5 January 2011 (UTC)

Criteria for inclusion of new theories[edit]

The recent addition of Zhang Ionocovalent Electronegativity, which also mentions a scale by Noorizadeh and Shakerzadeh, is starting to make me wonder about the criteria for inclusion of various scales in this article. These two are referenced solely on fairly recent articles by the scale-names' authors. Contrast that with others like Pauling and Allen and Sanderson and other scales, which are well-established in the literature and cited in review articles or other secondary sources. Is this article becoming starting to rely too much on primary sources (not necessarily reliable)? DMacks (talk) 11:22, 4 September 2011 (UTC)

I reverent this edit and also think this theory has undue weight since the article in International Journal of Molecular Sciences has not been cited yet.-Mys 721tx (talk) 13:42, 11 September 2011 (UTC)

Futhermore, two recent deletions in zhwp, zh:张永和 huilin and zh:Yonghe Zhang, claim that the theory created by Zhang "can also explain the mechanisms of life, universe, society, economy and politics." (my translation of the text). Is this a majority point of view? --Mys 721tx (talk) 13:55, 11 September 2011 (UTC)

New definition of electronegativity?[edit]

I've always understood fluorine to have the highest electronegativity, and the noble gasses to have zero electronegativity. Indeed, the periodic table that I'm looking at as I write this gives fluorine an electronegativity of 4, and all the noble gasses have an electronegativity of zero. What's going on?? — Preceding unsigned comment added by (talk) 22:10, 15 November 2011 (UTC)

This point of view is 50 years out of date. Before the discovery of the first noble gas compound in 1962, most chemists considered that noble gases could not be considered an electronegativity value, since electronegativity is the tendency of an atom to attract electrons in a compound and there were believed to be no noble gas compounds. Sometimes this was expressed by writing zero in tables, but it really meant unassigned.
However we now know that noble gases do form some compounds, so yes, they are assigned non-zero values of electronegativity. Dirac66 (talk) 01:14, 16 November 2011 (UTC)

Debate on Pauling Electronegativity[edit]

From "Debate with Pauling on Electronegativity" Yonghe Zhang American Huilin Institute

Pauling defined electronegativity in 1932 as the power of an atom in a molecule to attract electrons to itself [1]. The concept could be considered as an approximation of intuitively understanding the chemical bond strengths. However, the definition is not an unambiguous for the valence states [2-8]. And Pauling electronegativity scales, which based on much less a direct way of description by spectroscopy, unconditionally used and extended the limited situation of the linear difference of the thermochemical energy of two elements (H and Cl) to the all elements. And so that would inevitably mislead to the opposite wrong results [9-11]. Over the years, the attempts to derive a comprehensive quantitative scale of electronegativity have been disappointed because the lack of correlation between the experimental quantities and scale over a wide range of the electron quant configurations. In 1981-1982, on the basis of Bohr energy model,

E = - Z2me4/8n2h2ɛ02 = - RZ2/n2

Author obtained the effective principal quantum number n* and the effective quantum nuclear charge Z* from the ionization energy [2,3]:


Then the first scale of electronegativity in different valence states on spectroscopy corresponding quantum electron configurations of the orbital from 1s to nf was proposed [2,3]:

Xz = 0.241 n*( Iz /R) ½rc-2 + 0.775

where Iz is the ultimate ionization energy for outer electrons of the s, p, d and f orbital of the atom. R is the Rydberg constant, R = 22µ42e4/h2 = 13.6 eV, h is Planck’s constant and Z*=n*(Iz/R)½ is the effective nuclear charge Z* felt by the valence electron at the covalent boundary r.

Built-up the various quantum parameters of the atomic orbital Iz(s,p,d,f), n*,Z*, rc , rc-1 , n*rc-1 , based on spectroscopy, the electronegativity Xz formed a Method of the multiple-functional prediction, which can explain chemical observations of elements of all orbital electron configurations from 1s to nf, including the σ-bond, the linear or nonlinear combinations of ionic bond and covalent bond, the orbital spatial overlaps and the orbital spatial crosslinks. Therefore, this is what have been expected orbital ionization energy electronegativity that best meets Bergmann-Hinze criterion [5] and the Cherkasov conclusion [6].

After the above electronegativity published the author received hundreds of appreciation cards and letters. Henry Taube, Nobel Laureate, wrote in his letter: "Electronegativity continue to be a useful concept, and becomes even more useful when it is treated as a function of oxidation state." [12}. Mackay et al. pointed out that the major difficulty in Pauling's electronegativity is that the attraction for an electron is clearly not expected to be the same for different valencies of an element [8] and they encompassed in their university textbook the Zhang electronegativity in valencies.

But Pauling was still in confusion and continued to maintain his ambiguous valence state [13]: “I must say that I am not able to form a reliable opinion about the value of your work. I note that for a number of the elements your calculated values are close to my values of the electronegativity, and also that for other elements there is a considerable deviation. I suggest that you might discuss some property of the elements, in various compounds, and in different valence states, in order to find out whether or not your values are helpful in understanding the properties”.

To reply Pauling's concerns, the author published two papers “Electronegativities of elements in valence states and their applications” and “A scale for strengths of Lewis acids” [14], wherein 126 metal ion Lewis acids, in various compounds, and in different valence states, are calculated from a basic ionocovalent model established:

Z = z/r2 - 0.77 Xz + 8.0

Where Xz is Zhang electronegativity in valence states and z is the charge number of the atomic core (the number of valence electron). Z is Lewis acid strength. The Z values give a quantitative scale of the relative Pearson hardness or softness for various Lewis acids and agree fairly well with the Pearson classification [15] and the previous work [16-18].

From which Zhang ionocovalent theory is established [4,7]. The Zhang Lewis acid strengths Z, the Brown Lewis acid strength Sa, Portier ICP, Lenglet’s RP Relationship, “Electron-acceptor-Strength”, Scattering Cross Section Q and more applications are derived from Zhang electronegativity which has been widely quantitatively used over 30 years, forming an ionocovalency international schools [19]

The new papers not only satisfactorily replied Pauling’s concerns, but also give the author the conditions to develop the new ionocovalent theory that everything exists in Ionocovalency, the ionic energy harmonized with the covalent environment, that correlates with quantum potential and spectroscopy [9]:

I(Z*)(n*rc-1) = Ze2/r = n*(Iz/R)½ rc-1

There was no Pauling’s any review again and don’t know if Pauling had no more confusions? But someone is still in confusion.


[1] Pauling, L. J. Am. Chem. Soc. 1932, 54, 3570.

[2] Zhang, Y. J. Molecular Science 1 (1981) 125.

[3] Zhang, Y. Inorg Chem. 21 (1982) 3886.

[4] Portier, J.; Campet, G.; Etoumeau, J. and Tanguy, B. Alloys Comp.,1994a, 209, 59-64.

[5] D. Bergmann and J. Hinze. Angew, Chem. Int. Ed. Engl. 1996, 35, 150-163.

[6] A.R.Cherkasov, V.I.Galkin, E.M.Zueva, R.A.Cherkasov. Russian Chemical Reviews,67,5(1998) 375.

[7] Lenglet, M. Act. Passive Elec. Comp. 2004, 27, 1–60.

[8] Mackay, K. M.; Mackay, R. A.; Henderson W.,6th ed., Nelson Thomes, United Kingdom,2002,54.

[9] Zhang, Y. Int. J. Mol. Sci. 2010, 11, 4381-4406

[10] Villesuzanne, A.; Elissalde, C.; Pouchard, M. and Ravez, J. J.Eur.Phy.J.B. 6 (1998) 307.

[11] Ravez,J.; Pouchard,M.; Hagenmuller,P., Eur.J.Solid State Inorg.Chem.,1991, 25, 1107.

[12] Taube, H. a personal letter to Zhang, October 3, 1984.

[13] Pauling, L. a personal letter to Zhang, February 6, 1981.

[14] Zhang, Y. Inorg Chem. 21 (1982) 3889.

[15] Pearson, R. G., J. Am. Chem. Soc. 1963, 85, 3533; J. Chem. Educ.,1968, 45, 581.

[16] Klopman, G. J. Am. Chem. Soc. 1968, 90, 223.

[17] Yingst, A. and McDaniel, D. H. Inorg. Chem.1967, 6, 1076.

[18] Aharland, S. Chem. Phys. Lett., 1968, 2, 303; Struct. Bond., 1, 207.

[19] International Ionocovalency Schools - References:

1. Portier, J.; Campet, G.; Etoumeau, J. and Tanguy, B. Alloys Comp.,1994a, 209, 59-64.
2. Portier, J.; Campet, G.; Etoumeau, J. and Tanguy, B. Alloys Comp.,1994b, 209, 285.
3. Portier, J.; Campet, G. J. of the Korean Chem.Soc., 1997, 41, 8, 427-436.
4. Lenglet, M. Materials Research Bulletin, 2000, Vol. 35 (4) pp. 531-543.
5. Lenglet, M. Iono-covalent character of the metal-oxygen bonds in oxides: A comparison of
   experimental and theoretical data. Act. Passive Electron. Compon. 2004, 27, 1–60.
6. Wen,S.J.;Campet,G.;Portier,J.and J.Goodenough,Mat.Sci.and Eng.,B (accepted 1992)
7. Wen, S. J., doctoral thesis, University of Bordeaux I, 1992.
8. S.J.Wen,G.Campet,and J.P.Manaud,(1993) Active and Passive Elec.Comp., 1993, 15, 67-74  
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Fenhmm (talk) 00:11, 5 August 2013 (UTC)

The English in the above is not adequate, and not effective. Please find someone who speaks your language and is fluent in English and ask him/her to correct this post. Also, there seems to be no point to it. If you have an alternative electronegativity scale, then provide clear references to it and also provide clear documentation that it is being used outside a few small groups. Thanks! (talk) 23:47, 3 October 2013 (UTC)

Challenge to the definition of Electronegativity[edit]

The Pauling definition of electronegativity defines it for an atom. The reference cited in a feeble attempt to justify its use for groups, the IUPAC Gold book (on-line), contains three separate relevant entries: 1. Electronegativity - and as I already said defines it as an atomic property (to clarify: the property of an atom in a molecule, group, ion, etc.) 2. Group electronegativity which redirects to Substituent electronegativity and finally 3. Substituent electronegativity which is left undefined. I therefore challenge the definition as written here. In addition, there are NO references in the Group Electronegativity section. The link to the article on Hammett equation seems irrelevant at best. It describes the effect of substituents on the reaction of benzoic acid, and DOES NOT mention electronegativity at all. That is, it is not a general property defined for "groups" ------ It would also be nice if the article discussed the concepts real and profound inadequacies: including a complete inability to address stereochemical (directional) issues, the use of it in various contradictory ways in organic functional group discussions, and its near-complete inability to deal with the real valence charges as opposed to table entries. It is not a group property, in my opinion. If someone wants to claim it is, give us a good source. (talk) 23:35, 3 October 2013 (UTC)

Yes, the section on Group Electronegativity needs rewriting with proper sources. Two possible starting points which mention group electronegativity and cite several other references:
  1. M.A. Davis, J. Organic Chem. 1967, 32 (4), pp 1161–1163 Group electronegativity and polar substituent constants
  2. J.E. Huheey, Inorganic Chemistry (3rd ed. Harper and Row 1983) p.156-157 Group electronegativity. Dirac66 (talk) 00:53, 4 October 2013 (UTC)

Pauling electronegativity - misunderstanding[edit]

Firstly there is a misunderstanding in the article- Pauling specifically ignored the contribution of ionic canonicals in his derivation of electronegativity. This was because the ionic contributuon in H2 as calculated by Coolidge et al was small. Pauling made the assumption, not an unreasonable one, that this would be true for all homonuclear bonds. The covalent bond energy of A-B was taken as the geometric mean of the actual bond energies of A-A and B-B. The difference between actual bond energy of A-B and the calculated geometric mean was the "ionic contribution" which was taken to be due to the difference between the electronegativities of A and B. Secondly when he first introduced it the units were eV ( the units he used for bond energies). I do not know when the scale was arbitrarily made dimensionless.Axiosaurus (talk) 16:37, 10 January 2015 (UTC)

On looking at the formulas it would seem that Pauling EN should be (ev)1/2 if it is not made dimensionless. Mulliken EN on the other hand should be (eV), and Allred-Rochow EN should be electron/pm2 (or electron/Å2 in older units). This variety of units is of course possible because EN is not a directly measurable or well-defined quantity. Perhaps the scale was arbitrarily made dimensionless because people threw up their hands and decided to forget about units when dealing with EN. Dirac66 (talk) 17:29, 16 January 2015 (UTC)

Pauling Electronegativity Disadvantage and Improvement[edit]

The main disadvantage of Pauling electronegativity [1-10] is not considered the different valence of element and can not be used to the quantitative applications. Zhang proposed a electronegativity in valence states, for which Pauling failed to issue a reliable opinion. Pauling proposed[11]to discuss the properties of compounds of elements of different valence to illustrate if the Zhang electronegativity is useful. Over decades, let us see what is the result. The following examples are cited to release Pauling’s confusion. Many chemical phenomena which involved the different valence state can be satisfactorily explained by Zhang electronegativity or ionocovalency, but Pauling electronegativity demonstrated incompetence, it can not be used for quantitative applications and even draw the wrong conclusions.

Carbon, Sulphur, P-elements and Hydrogen

There are some arguments about the values of electronegativities of carbon, sulphur, selenium, tellurium, iodine and hydrogen [12]. The Chart 1 shows IC values in the order:

Se2+ (3.146) > S2+ (3.121) > C2+ (2.998) > Te2+ (2.832) > I+ (2.530) > H+ (2.297)

The results are consistent with the observations that hydrides H2Se, H2S, H2C, H2Te and HI form H3O+ ions in water [13] . As Thomas reviewed, the electronegativity of carbon and sulphur in most of the scale are almost identical. The key point, however, so far as their role as poisons is concerned, is that they differ markedly in the distance at which they sit on the nickel overlayers [14]. The calculations for these locations show that sulphur is very much stronger than carbon as a poison. The results are also consistent with the experiment data of the dipole moment which indicates that the electron clouds on the C-S and C-I bond in the molecules CS2 and CI4 are close to the sulphur end and the iodine end, respectively [15]. From IC model data (IonocovalencyChart) we can see that S6+ has a greater ionicity than that of C4+: Iav (S6+ = 46.077, C4+ = 37.015), although they have the close spatial covalency, n*rc-1 (C4+ = 2.618, S6+ = 2.805) (Ionocovalency Parameters).

Retrieve of Pauling Erroneous Covalency Results

In study on the role of covalency in ferroelectric niobates and tantalites Villesuzanne et al. [7], the fact that Ta5+-O bonds are more covalent than Nb5+-O bonds is due to a larger radial expansion of Ta 5d orbitals, leading to a greater overlap with oxygen 2p orbitals. This effect is not accounted for in Pauling electronegativity scales [16], which give information on the energy difference between valence orbitals, not on their spatial overlap. The arguments led to the opposite assumption of reference [17] concerning the covalency of Ta5+-O and Nb5+-O bonds from Pauling electronegativity Xp: Ta(1.5) < Nb(1.6). In their later paper, they proposed that the explicit calculation of the electronic structure give a larger covalency for Ta5+-O bonds than for Nb5+-O bonds. This result is retrieved in Zhang electronegativity scales for ions [1,8]. The results can be fairly well accounted in IC model [10]: The energies of Ta 5d and Nb 4d atomic orbitals are the same in EHTB parameters due to they have similar atomic ionicity Iav of 24.89 and 27.02 respectively (Ionocovalency Parameters). The bond lengths are equal due to they have similar linear covalency rc-1 of 0.745 and 0.745 respectively. The big difference is the spatial covalency, n*rc-1, in I(Iav )C(n*rc-1) = n*(Iav/R)½rc-1. The Ta 5d orbitals, compared to Nb 4d orbitals, involved the greater spatial covalency, n*rc-1, (Ta5+ = 3.246, Nb5+ = 2.869), leading to a greater overlap with oxygen 2p orbitals and a greater IC: Ta5+ (4.393) > Nb5+ (4.043) and XIC: Ta5+ (2.197) > Nb5+ ( 2.053).

Mössbauer Parameters δ and Δ

As the IC model, n*(Iav/R)½rc-1. is defined as ionocovalent density of the effective nuclear charges at covalent boundary, it strongly related with the Mössbauer parameters δ and Δ. [18.19]. The value of the isomer shift,δ, depends particularly on the density of s electrons at the nucleus. Therefore, in iron-57 an increase in electron density causes a negative isomer shift; since d electrons tend to shield the nucleus slightly from the s electrons the value of δ falls as the number of d electrons in the iron atom falls. Mean values of δ [20], Z* and IC for some oxidation states of iron are shown in Table 1:

Table 1. IC, Z* and δ for Iron-57.

Iron-57 FeI FeII FeIII FeIV FeV
δ/mm s-1 2.3 1.5 0.7 0.2 -0.6
Z*= n*(Iav/R)½ 2.624 3.245 3.997 4.896 5.684
IC=n*(Iav/R)½rc1 2.253 2.786 3.431 4.203 4.879

Inert Pair Effect (6s2 Elements)

The IC model based on the VB approximation intuitively appealing and determined by covalent radius and ionization energy is in accord with the relativistic effects with which contributions to the unusual chemistry of the heavier elements are two principal consequences. First, the s orbitals become more stable. The second, d and f orbitals expand and their energies are less. For the inert pair effect in Tl(I), Pb(II), and Bi(III), the Relativistic effects can give a qualitative verbalize: “The s orbitals of the heavier elements become more stable than otherwise expected” [21]. In IC model, as shown in Table 2, the effect is attributable to the fact that the bond property in this case is controlled by the ionic function I(Iz, Iav). They are more stable in ionic compounds than in the entirely covalent form. Their IEs for forming higher covalent bonds are too much higher to form a stable hybridizing ionicity Iav:

Table 2. Atomic Parameters of Tl, Pb and Bi.

Cations Tl+ Tl2+ Tl3+ Pb2+ Pb3+ Pb4+ Bi3+ Bi4+ Bi5+
Iz 6.11 20.4 29.8 15 32 42.3 25.6 45.3 56
Iav 6.11 13.26 18.77 11.21 18.14 24.18 16.63 23.72 30.18
XIC 1.16 1.59 1.75 1.45 1.74 1.94 1.69 1.95 2.15
IC 1.89 2.92 3.31 2.68 3.44 3.78 3.16 3.81 4.27


[1] Zhang, Y. J. MolecularScience 1 (1981) 125.

[2] Zhang, Y. Inorg Chem. 21 (1982) 3886.

[3] A. R. Cherkasov, V. I. Galkin, E.M. Zueva, R. A. Cherkasov, Russian Chemical Reviews, 67, 5(1998) 375-392.

[4] Datta,D. Proceedings of the Indian Academy of Sciences - Chemical Sciences Volume 100, 6 (1988) 549-557

[5] Portier, J.; Campet, G.; Etoumeau, J. and Tanguy, B. Alloys Comp.,1994a, 209, 59-64.

[6] D. Bergmann and J. Hinze. Angew,Chem. Int. Ed. Engl. 1996, 35, 150-163.

[7] Villesuzanne, A.; Elissalde, C.;Pouchard, M. and Ravez, J. J. Eur. Phy. J. B. 6 (1998) 307.

[8] Mackay, K. M.; Mackay, R. A.;Henderson W. "Introduction to Modern Inorganic Chemistry",6th ed., Nelson Thornes, United Kingdom, 2002, pp 53-54.

[9] Lenglet, M. Iono-covalent character of the metal-oxygen bonds inoxides: A comparison of experimental and theoretical data. Act.Passive Electron. Compon.2004, 27, 1–60.

[10] Zhang, Y. Ionocovalency and Applications 1. Ionocovalency Model andOrbital Hybrid Scales.Int. J. Mol. Sci. 2010,11,4381-4406

[11] Pauling, L. A personal letter to Zhang, February 6, 1981.

[12] Li, Z.-H.; Dai, Y.-M.; Wen, S.-N.; Nie, C.-M.; Zhou, C.-Y. Relationship between atom valence shell electron quantum topological indices and electronegativity of elements. Acta Chimica. Sinica. 2005, 14, 1348.

[13] Dalian Technology Institute. Inorg. Chem. (in Chinese); 3rd ed.; High Education Press: Beijing, China, 1990; pp. 638, 804.

[14] Thomas, J.M. Principles and Practice of Heterogeneous Catalysis; Wiley-VCH: Weinheim, Germany, 1996; p. 448.

[15] Xu, G.-X. Material Structure (in Chinise); People’s Education Press: Beijing, China, 1961; p. 160.

[16] Pauling, L. J. Am. Chem. Soc. 1932, 54, 3570.

[17] Ravez, J.; Pouchard, M.; Hagenmuller, P., Eur. J.Solid State Inorg. Chem., 1991, 25, 1107.

[18] Reguera, E.; Bertran, J.F.; Miranda, J.; Portilla, C. Study of the dependence of Mossbauer parameters on the outer cation in nitroprussides. J. Radioanal. Nucl. Chem. Lett. 1992, 3, 191–201.

[19] Reguera, E.; Rodriguez-Hernandez, J.; Champi, A.; Duque, J.G.; Granado, E.; Rettori, C. Unique

[20] Heslop, R.B. Jones, K. Inorganic Chemistry; Elsevier Scientific Publishing: Amsterdam, Netherland, 1976; p. 31.

[21] Pyykkö, P. Relativistic Effects in Structural Chemistry. Chem. Rev. 2002, 3, 563–594.

Thanks! Fenhmm (talk) 19:03, 3 January 2016 (UTC)

Cesium and francium[edit]

The last paragraph of the intro attempts to explain why Cs is considered more electronegative than Fr in 3-4 lines with no sources. After explaining that I(Fr) > I(Cs), the last clause says and this in turn implies that caesium is in fact more electronegative than francium. This was removed today without explanation by 2605:a000:1317:12f:48f8:c48e:c582:4648, and restored without comment by DMacks. Actually I agree with the numbered user that the inclusion of this clause is not justified at this point since it raises several unanswered questions: why must the electronegativity trend follow the ionization energy trend? if the Pauling scale is implied here, what about the electron affinity trend? or would it be better to consider the Allen scale for which the table does show EN(Cs) > EN(F), which is not true for the Pauling scale. And what are the sources for the values and for the explanations?

I think these questions should be answered before stating that EN(Cs) > EN(Fr), but not in the introduction before we have defined the different scales of electronegativity. Instead I propose that (1) the intro should stop after Caesium is the least electronegative element in the periodic table (=0.79), while fluorine is most electronegative (=3.98). and (2) the 3-4 lines on Cs and Fr should be moved to the section on Periodic trends, where the necessary explanations and sources can be included. Dirac66 (talk) 00:25, 20 January 2016 (UTC)