Electronegativity

The Concept of Electronegativity in Chemistry.

The concept of electronegativity was introduced by Linus Pauling in the 1930s: The electronegativity Χ of a chemical element is the relative measure, expressed in numbers, of the tendency to attract the electron pair of a bond. The bonding partner with the higher electronegativity is referred to as electronegative, and the one with the lower electronegativity is referred to as electropositive. The electronegativity difference Δ_EN allows statements to be made about the bond type and reaction of the partners in question.

In addition to the relative, dimensionless electronegativity scale according to Pauling - which is still very commonly used - several other approaches have been developed over time that consider electronegativities using quantitative methods (see the table below); the electronegativity values according to Allen, Mulliken, Sanderson and Allred-Rochow were taken into account here. The last two columns contain the values according to Ghosh-Gupta and Pearson, each in electron volts eV.

Linus Pauling initially calculated the electronegativity from the bond enthalpies and initially obtained rounded data [see column 1]. However, the resulting values did not prove to be additive quantities, i.e., for example, the condition Δ_C-F - Δ_C-Cl = Δ_F-Cl (Δ = difference in electronegativities) is not fulfilled.

According to Pauling, the difference in electronegativity between atoms A and B is expressed by the following equation (E_d = dissociation energies in eV):

electronegativity calculation by pauling

The scale was chosen so that the relative electronegativity of hydrogen Χ_R is equal to 2.1. The sign of the square root was chosen intuitively by Pauling [11].

diagram: electronegativity by Pauling

diagram: electronegativity by Allred-Rochow

Electronegativity of the Elements

Z	Element		Pauling orig.	Pauling	Allen	Mulliken	Sander- son	Allred- Rochow	Ghosh- Gupta [eV]	Pearson [eV]
			[1]	[2]	[3]	[4]	[5]	[6]	[7]	[8]
1	Hydrogen	H	2.1	2.20	2.300	2.8	2.31	2.20	7.1862	7.18
2	Helium	He			4.160			5.50	12.0568
3	Lithium	Li	1.0	0.98	0.912	1.3	0.86	0.97	2.4435	3.01
4	Beryllium	Be	1.5	1.57	1.576		1.61	1.47	3.7060	4.9
5	Boron	B	2.0	2.04	2.051	1.8	1.88	2.01	4.9686	4.29
6	Carbon	C	2.5	2.55	2.544	2.5	2.47	2.50	6.2338	6.27
7	Oxygen	N	3.0	3.04	3.066	2.9	2.93	3.07	7.4964	7.30
8	Nitrogen	O	3.5	3.44	3.610	3.0	3.46	3.50	8.7861	7.54
9	Fluorine	F	4.0	3.98	4.193	4.1	3.92	4.10	10.0378	10.41
10	Neon	Ne			4.789			4.84	11.3003
11	Sodium	Na	0.9	0.93	0.869	1.2	0.85	1.01	2.4380	2.85
12	Magnesium	Mg	1.2	1.31	1.293		1.42	1.23	3.6108	3.75
13	Aluminium	Al	1.5	1.61	1.613	1.4	1.54	1.47	4.6393	3.23
14	Silicon	Si	1.8	1.9	1.916	2.0	1.74	1.74	5.5236	4.77
15	Phosphorus	P	2.1	2.19	2.253	2.3	2.16	2.06	6.3405	5.62
16	Sulfur	S	2.5	2.58	2.589	2.5	2.66	2.44	6.8379	6.22
17	Chlorine	Cl	3.0	3.16	2.869	3.3	3.28	2.83	7.2923	8.30
18	Argon	Ar			3.242		3.92	3.20	7.6515
19	Potassium	K	0.8	0.82	0.734	1.1	0.74	0.91	2.0027	2.42
20	Calcium	Ca	1.0	1.00	1.034		1.06	1.04	2.6965	2.2
21	Scandium	Sc	1.3	1.36	1.19		1.09	1.20	2.8571	3.34
22	Titanium	Ti	1.5	1.54	1.38			1.32	3.0040	3.45
23	Vanadium	V	1.6	1.63	1.53			1.45	3.1482	3.6
24	Chromium	Cr	1.6	1.66	1.65			1.56	3.2951	3.72
25	Manganese	Mn	1.5	1.55	1.75			1.60	3.4349	3.72
26	Iron	Fe	1.8	1.83	1.80			1.64	3.5836	4.06
27	Cobalt	Co	1.8	1.88	1.84			1.70	3.7305	4.3
28	Nickel	Ni	1.8	1.91	1.88			1.75	3.8584	4.40
29	Copper	Cu	1.9	1.90	1.85			1.75	4.0026	4.48
30	Zinc	Zn	1.6	1.65	1.59		1.86	1.66	4.1332	4.45
31	Gallium	Ga	1.6	1.81	1.756	1.4	2.10	1.82	4.6638	3.2
32	Germanium	Ge	1.8	2.01	1.994	1.9	2.31	2.02	5.1318	4.6
33	Arsenic	As	2.0	2.18	2.211	2.2	2.53	2.20	5.5372	5.3
34	Selenium	Se	2.4	2.55	2.434	2.4	2.76	2.48	5.8746	5.89
35	Bromine	Br	2.8	2.96	2.685	3.0	2.96	2.74	6.1658	7.59
36	Krypton	Kr		2.90	2.966		3.17	2.94	6.3916
37	Rubidium	Rb	0.8	0.82	0.706	1.0	0.70	0.89	2.0135	2.34
38	Strontium	Sr	1.0	0.95	0.963		0.96	0.99	2.5849	2.0
39	Yttrium	Y	1.2	1.22	1.12	1.4	0.98	1.11	2.7237	3.19
40	Zirconium	Zr	1.4	1.33	1.32			1.22	2.8489	3.64
41	Niobium	Nb	1.6	1.60	1.41			1.23	2.9740	4.0
42	Molybdenum	Mo	1.8	2.16	1.47			1.30	3.0992	3.9
43	Technetium	Tc	1.9	1.90	1.51			1.36	3.2244
44	Ruthenium	Ru	2.2	2.20	1.54			1.42	3.3360	4.5
45	Rhodium	Rh	2.2	2.28	1.56			1.45	3.4611	4.30
46	Palladium	Pd	2.2	2.20	1.59			1.35	3.5727	4.45
47	Silver	Ag	1.9	1.93	1.87			1.42	3.6842	4.44
48	Cadmium	Cd	1.7	1.69	1.52		1.73	1.46	3.7958	4.33
49	Indium	In	1.7	1.78	1.656	1.3	1.88	1.49	4.253	3.1
50	Tin	Sn	1.8	1.96	1.824	1.8	2.02	1.72	4.672	4.30
51	Antimony	Sb	1.9	2.05	1.984	2.0	2.19	1.82	5.0203	4.85
52	Tellurium	Te	2.1	2.10	2.158	2.2	2.34	2.01	5.3250	5.49
53	Iodine	I	2.5	2.66	2.359	2.7	2.50	2.21	3.5836	6.76
54	Xenon	Xe			2.582		2.63	2.40	5.8121
55	Cesium	Cs	0.7	0.79	0.659	1.0	0.69	0.86		2.18
56	Barium	Ba	0.9	0.89	0.881		0.93	0.97		2.4
57	Lanthanum	La	1.1	1.10	1.09		0.92	1.08		3.1
58	Cerium	Ce	1.1	1.12				1.08
59	Praseodymium	Pr	1.1	1.13				1.07
60	Neodymium	Nd	1.1	1.14				1.07
61	Promethium	Pm	1.1	1.13				1.07
62	Samarium	Sm	1.1	1.17				1.07
63	Europium	Eu	1.1	1.20				1.01
64	Gadolinium	Gd	1.1	1.20				1.11
65	Terbium	Tb	1.1	1.20				1.10
66	Dysprosium	Dy	1.1	1.22				1.10
67	Holmium	Ho	1.1	1.23				1.10
68	Erbium	Er	1.1	1.24				1.11
69	Thulium	Tm	1.1	1.25				1.11
70	Ytterbium	Yb	1.1	1.10				1.06
71	Lutetium	Lu	1.1	1.27				1.14
72	Hafnium	Hf	1.3	1.30	1.16			1.23		3.8
73	Tantalum	Ta	1.5	1.50	1.34			1.33		4.11
74	Tungsten	W	1.7	2.36	1.47			1.40		4.40
75	Rhenium	Re	1.9	1.90	1.60			1.46		4.02
76	Osmium	Os	2.2	2.20	1.65			1.52		4.9
77	Iridium	Ir	2.2	2.20	1.68			1.55		5.4
78	Platinum	Pt	2.2	2.28	1.72			1.44		5.6
79	Gold	Au	2.4	2.54	1.92			1.42		5.77
80	Mercury	Pa	1.9	2.00	1.76		1.92	1.44		4.91
81	Thallium	Tl	1.8	2.04	1.789		1.96	1.44		3.2
82	Lead	Pb	1.8	2.33	1.854		2.01	1.55		3.90
83	Bismuth	Bi	1.9	2.02	2.01		2.06	1.67		4.69
84	Polonium	Po	2.0	2.00	2.39			1.76
85	Astatine	At	2.2	2.20	2.60			1.90
86	Radon	Rn						2.06
87	Francium	Fr	0.7	0.70				0.86
88	Radium	Ra	0.9	0.90				0.97
89	Actinium	Ac	1.1	1.10				1.00
90	Thorium	Th	1.3	1.30				1.11
91	Protactinium	Pa	1.5	1.50				1.14
92	Uranium	U	1.7	1.38				1.22
93	Neptunium	Np	1.3	1.36				1.22
94	Plutonium	Pu	1.3	1.28				1.22
95	Americium	Am	1.3	1.30				1.2
96	Curium	Cm	1.3	1.30				1.2
97	Berkelium	Bk	1.3	1.30				1.2
98	Californium	Cf	1.3	1.30				1.2
99	Einsteinium	Es	1.3	1.30				1.2
100	Fermium	Fm	1.3	1.30				1.2
101	Mendelevium	Md	1.3	1.30				1.2
102	Nobelium	No	1.3	1.30				1.2
103	Lawrencium	Lr	1.3	1.30
104	Rutherfordium	Rf
105	Dubnium	Db
106	Seaborgium	Sg
107	Bohrium	Bh
108	Hassium	Hs
109	Meitnerium	Mt
110	Darmstadtium	Ds
111	Roentgenium	Rg
112	Copernicium	Cn
113	Nihonium	Nh
114	Flerovium	Fl
115	Moscovium	Mc
116	Livermorium	Lv
117	Tennessine	Ts
118	Oganesson	Og

References:

[1, 2] - Pauling´s scale of electronegativity

* [1.1] - Linus Pauling: The Nature of the Chemical Bond. IV. The Energy of Single Bonds and the Relative Electronegativity of Atoms. ''Journal of the American Chemical Society'', 1932, DOI 10.1021/ja01348a011.

[3] - Electronegativity by Allen scale

* [2] - Leland C. Allen: Electronegativity is the average one-electron energy of the valence-shell electrons in ground-state free atoms. ''Journal of the American Chemical Society'', 1989, DOI 10.1021/ja00207a003.

[4] - Mulliken scale of electronegativity

* [3.1] - A New Electroaffinity Scale; Together with Data on Valence States and on Valence Ionization Potentials and Electron Affinities. ''Journal of Chemical Physics'', 1934, DOI 10.1063/1.1749394.

* [3.2] - Robert S. Mulliken: Electronic Structures of Molecules XI. Electroaffinity, Molecular Orbitals and Dipole Moments. ''Journal of Chemical Physics'', 1935, DOI 10.1063/1.1749731.

[5] - Sanderson scale of electronegativity

* [5.1] - R. T. Sanderson: Electronegativity and bond energy. ''Journal of the American Chemical Society'', 1983, DOI 10.1021/ja00346a026.

* [5.2] - R. T. Sanderson: Principles of electronegativity Part I. General nature. ''Journal of Chemical Education'', 1988, DOI 10.1021/ed065p112.

* [5.3] - R. T. Sanderson: Principles of electronegativity Part II. Applications. ''Journal of Chemical Education'', 1988, DOI 10.1021/ed065p227.

* R. T. Sanderson: Polar Covalence. Academic Press, 1983, ISBN 0-12-618080-6.

[6] - Allred-Rochow electronegativity values

* [6.1] - A.L. Allred, E.G. Rochow: A scale of electronegativity based on electrostatic force. ''Journal of Inorganic and Nuclear Chemistry'', 1958, DOI 10.1016/0022-1902(58)80003-2.

* [6.2] - A.L. Allred: Electronegativity values from thermochemical data.''Journal of Inorganic and Nuclear Chemistry'', 1961, DOI 10.1016/0022-1902(61)80142-5.

[7] - Ghosh und Gupta electronegativity values

* [7.1] - Dulal C. Ghosh, Kartick Gupta: A New Scale Of Electronegativity Of 54 Elements Of Periodic Table Based On Polarizability Of Atoms. ''Journal of Theoretical and Computational Chemistry'', 2006, DOI 10.1142/S0219633606002726.

[8] - Pearson scale of electronegativity

* [8.1] - Ralph G. Pearson: Absolute electronegativity and hardness: application to inorganic chemistry, ''Inorganic Chemistry'' (1988), DOI dx.doi.org/10.1021/ic00277a030.

[9] - Smith scale of electronegativity [Werte hier nicht abgebildet]

* [9.1] - Derek W. Smith: Electronegativity in two dimensions: Reassessment and resolution of the Pearson-Pauling paradox. ''Journal of Chemical Education'', (1990), DOI 10.1021/ed067p911.

[10] - Nagle scale of electronegativity [data not specified here]

* [10.1] - Jeffrey K. Nagle: Atomic polarizability and electronegativity. ''Journal of the American Chemical Society'', (1990), DOI 10.1021/ja00168a019.

Further literature sources:

* [11] - Electronegativity. Definition, IUPAC Gold Book, DOI 10.1351/goldbook.E01990.

* Linus Pauling (Heinrich Noller): Die Natur der chemischen Bindung, Verlag Chemie 1962, ISBN 3527252177, ISBN 978-3527252176.

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