489:-electrons. Valence bond treatments are restricted to relatively small molecules, largely due to the lack of orthogonality between valence bond orbitals and between valence bond structures, while molecular orbitals are orthogonal. On the other hand, valence bond theory provides a much more accurate picture of the reorganization of electronic charge that takes place when bonds are broken and formed during the course of a chemical reaction. In particular, valence bond theory correctly predicts the dissociation of homonuclear diatomic molecules into separate atoms, while simple molecular orbital theory predicts dissociation into a mixture of atoms and ions. For example, the molecular orbital function for
438:-orbital electrons is a sigma bond, because two spheres are always coaxial. In terms of bond order, single bonds have one sigma bond, double bonds consist of one sigma bond and one pi bond, and triple bonds contain one sigma bond and two pi bonds. However, the atomic orbitals for bonding may be hybrids. Often, the bonding atomic orbitals have a character of several possible types of orbitals. The methods to get an atomic orbital with the proper character for the bonding is called
404:
415:
344:
would become what some have called the bible of modern chemistry. This book helped experimental chemists to understand the impact of quantum theory on chemistry. However, the later edition in 1959 failed to adequately address the problems that appeared to be better understood by molecular orbital
249:
suggested in 1921 that eight and eighteen electrons in a shell form stable configurations. Bury proposed that the electron configurations in transitional elements depended upon the valence electrons in their outer shell. In 1916, Kossel put forth his theory of the
372:, but where a single Lewis structure cannot be written, several valence bond structures are used. Each of these VB structures represents a specific Lewis structure. This combination of valence bond structures is the main point of
528:
An important aspect of the valence bond theory is the condition of maximum overlap, which leads to the formation of the strongest possible bonds. This theory is used to explain the covalent bond formation in many molecules.
493:
is an equal mixture of the covalent and ionic valence bond structures and so predicts incorrectly that the molecule would dissociate into an equal mixture of hydrogen atoms and hydrogen positive and negative ions.
512:, either centered each on one atom to give a classical valence bond picture, or centered on all atoms in the molecule. The resulting energies are more competitive with energies from calculations where
349:
programs. Since the 1980s, the more difficult problems, of implementing valence bond theory into computer programs, have been solved largely, and valence bond theory has seen a resurgence.
285:
equation both derived in 1925. However, for hydrogen alone, in 1927 the
HeitlerâLondon theory was formulated which for the first time enabled the calculation of bonding properties of the
1300:
277:
Although there is no mathematical formula either in chemistry or quantum mechanics for the arrangement of electrons in the atom, the hydrogen atom can be described by the
580:
Using modern classical valence bond theory, Patil and
Bhanage have shown that the cation-anion interface of protic ionic liquids possesses charge shift bond character.
454:, which does not adhere to the valence bond idea that electron pairs are localized between two specific atoms in a molecule but that they are distributed in sets of
340:
Linus
Pauling published in 1931 his landmark paper on valence bond theory: "On the Nature of the Chemical Bond". Building on this article, Pauling's 1939 textbook:
392:
should be in the bond region. Valence bond theory views bonds as weakly coupled orbitals (small overlap). Valence bond theory is typically easier to employ in
188:
333:, this period marks the start of "modern valence bond theory", as contrasted with older valence bond theories, which are essentially electronic theories of
462:
and ionization properties in a straightforward manner, while valence bond theory gives similar results but is more complicated. Valence bond theory views
345:
theory. The impact of valence theory declined during the 1960s and 1970s as molecular orbital theory grew in usefulness as it was implemented in large
1001:
508:
Modern valence bond theory replaces the overlapping atomic orbitals by overlapping valence bond orbitals that are expanded over a large number of
88:
181:
266:
put forward a theory similar to Lewis' only his model assumed complete transfers of electrons between atoms, and was thus a model of
478:
76:
652:
577:
orbital of F, each containing an unpaired electron. Mutual sharing of electrons between H and F results in a covalent bond in HF.
110:
545:
orbitals of the two F atoms, each containing an unpaired electron. Since the nature of the overlapping orbitals are different in H
1336:
1307:
72:
241:
proposed that a chemical bond forms by the interaction of two shared bonding electrons, with the representation of molecules as
122:
118:
1239:
994:
921:
711:
174:
164:
1343:
317:
used the pair bonding ideas of Lewis together with
HeitlerâLondon theory to develop two other key concepts in VB theory:
92:
1410:
1032:
627:
987:
126:
1384:
728:
Cooper, David L.; Gerratt, Joseph; Raimondi, Mario (1986). "The electronic structure of the benzene molecule".
1442:
1270:
225:
of the dissociated atoms combine to give individual chemical bonds when a molecule is formed. In contrast,
1478:
156:
368:
atomic orbitals of each atom containing one unpaired electron. A valence bond structure is similar to a
1493:
1483:
939:"Modern ab initio valence bond theory calculations reveal charge shift bonding in protic ionic liquids"
589:
503:
140:
54:
46:
152:
1488:
1260:
1244:
426:
The overlapping atomic orbitals can differ. The two types of overlapping orbitals are sigma and pi.
133:
103:
80:
938:
1219:
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148:
61:
50:
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68:
298:
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114:
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structures. In contrast, molecular orbital theory views aromaticity as delocalization of the
439:
373:
322:
318:
1452:
1437:
1145:
878:
833:
784:
737:
643:
513:
246:
31:
22:
8:
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1265:
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Walther Kossel, âUber
Molkulbildung als Frage der Atombauâ, Ann. Phys., 1916, 49:229â362.
690:
334:
96:
882:
837:
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occur when two orbitals overlap when they are parallel. For example, a bond between two
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408:
346:
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and they worked out the details of the theory over the course of the night. Later,
282:
259:
160:
1184:
869:
Harcourt, Richard D. (1987). "The electronic structure of the benzene molecule".
377:
369:
326:
271:
242:
84:
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which can extend over the entire molecule. Molecular orbital theory can predict
1127:
1111:
1106:
1022:
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222:
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1316:
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467:
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314:
306:
218:
144:
1457:
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393:
310:
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979:
648:"Langmuir's Theory of the Arrangement of Electrons in Atoms and Molecules"
1101:
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482:
463:
385:
238:
665:
1083:
1067:
1057:
954:
490:
427:
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reference wavefunction. The most recent text is by Shaik and
Hiberty.
430:
occur when the orbitals of two shared electrons overlap head-to-head.
1205:
890:
846:
821:
797:
772:
749:
564:
In an HF molecule the covalent bond is formed by the overlap of the 1
459:
389:
202:
647:
1072:
286:
270:. Both Lewis and Kossel structured their bonding models on that of
1062:
937:
Patil, Amol
Baliram; Bhanage, Bhalchandra Mahadeo (17 May 2016).
471:
431:
1285:
305:
join together, with plus, minus, and exchange terms, to form a
553:
molecules, the bond strength and bond lengths differ between H
477:. This is essentially still the old idea of resonance between
403:
400:
remain essentially unchanged during the formation of bonds.
376:
theory. Valence bond theory considers that the overlapping
293:
based on quantum mechanical considerations. Specifically,
414:
714:â Key participants in the development of Linus Pauling's
911:
614:
Murrell, J. N.; Kettle, S. F. A.; Tedder, J. M. (1985).
727:
18:
One of two foundational theories of quantum chemistry
613:
536:molecule, the FâF bond is formed by the overlap of
258:), also independently advanced in the same year by
822:"The electronic structure of the benzene molecule"
615:
1470:
820:Messmer, Richard P.; Schultz, Peter A. (1987).
819:
773:"Electronic structure of the benzene molecule"
364:is formed between two atoms by the overlap of
1301:
995:
912:Shaik, Sason S.; Phillipe C. Hiberty (2008).
209:is one of the two basic theories, along with
182:
936:
445:
229:has orbitals that cover the whole molecule.
213:, that were developed to use the methods of
1009:
497:
89:Multi-configurational self-consistent field
1308:
1294:
1002:
988:
407:Ï bond between two atoms: localization of
189:
175:
21:"VBT" redirects here. For other uses, see
845:
796:
384:. Because of the overlapping, it is most
914:A Chemist's Guide to Valence Bond Theory
868:
653:Journal of the American Chemical Society
413:
402:
111:Time-dependent density functional theory
73:Semi-empirical quantum chemistry methods
1337:Sickle Cell Anemia, a Molecular Disease
770:
622:(2nd ed.). John Wiley & Sons.
1471:
479:Friedrich August Kekulé von Stradonitz
337:couched in pre-wave-mechanical terms.
123:Linearized augmented-plane-wave method
119:Orbital-free density functional theory
1289:
983:
301:(1926) to show how two hydrogen atom
642:
943:Physical Chemistry Chemical Physics
309:. He then called up his associate
93:Quantum chemistry composite methods
13:
1351:How to Live Longer and Feel Better
916:. New Jersey: Wiley-Interscience.
466:properties of molecules as due to
380:of the participating atoms form a
342:On the Nature of the Chemical Bond
77:MĂžllerâPlesset perturbation theory
14:
1505:
1411:International League of Humanists
1315:
1033:Introduction to quantum mechanics
532:For example, in the case of the F
450:Valence bond theory complements
329:, author of the noted 1952 book
1385:Pauling Electronegativity Scale
1331:The Nature of the Chemical Bond
930:
905:
716:The Nature of the Chemical Bond
523:
127:Projector augmented wave method
862:
813:
764:
721:
705:
696:
680:
636:
607:
1:
1344:Vitamin C and the Common Cold
600:
211:molecular orbital (MO) theory
165:KorringaâKohnâRostoker method
693:, and (Pauling, 1960, p. 5).
7:
583:
398:core orbitals and electrons
357:According to this theory a
299:Schrödinger's wave equation
157:Empty lattice approximation
10:
1510:
590:Modern valence bond theory
504:Modern valence bond theory
501:
232:
141:Nearly free electron model
55:Modern valence bond theory
20:
1443:Intravenous ascorbic acid
1419:
1398:
1360:
1323:
1253:
1227:
1218:
1193:
1167:
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1125:
1081:
1050:
1043:
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516:is introduced based on a
446:Comparison with MO theory
418:Two p-orbitals forming a
352:
134:Electronic band structure
104:Density functional theory
81:Configuration interaction
1220:Molecular orbital theory
691:University City TĂŒbingen
498:Computational approaches
452:molecular orbital theory
227:molecular orbital theory
221:. It focuses on how the
207:valence bond (VB) theory
149:Muffin-tin approximation
62:Molecular orbital theory
51:Generalized valence bond
1406:Linus Pauling Institute
771:Pauling, Linus (1987).
687:University College Cork
153:k·p perturbation theory
568:orbital of H and the 2
423:
411:
297:determined how to use
47:CoulsonâFischer theory
1373:Orbital hybridisation
595:Valence bond programs
417:
406:
325:(1930). According to
323:orbital hybridization
1438:Vitamin C megadosage
514:electron correlation
279:Schrödinger equation
247:Charles Rugeley Bury
32:Electronic structure
23:VBT (disambiguation)
1448:Linus Pauling Award
1368:Valence bond theory
1160:Valence bond theory
949:(23): 15783â15790.
883:1987Natur.329..491H
838:1987Natur.329..492M
789:1987Natur.325..396P
742:1986Natur.323..699C
666:10.1021/ja01440a023
366:half filled valence
252:ionic chemical bond
97:Quantum Monte Carlo
69:HartreeâFock method
40:Valence bond theory
1479:Chemistry theories
1433:Molecular medicine
955:10.1039/C6CP02819E
456:molecular orbitals
424:
412:
115:ThomasâFermi model
1494:General chemistry
1484:Quantum chemistry
1466:
1465:
1427:Ava Helen Pauling
1283:
1282:
1279:
1278:
1254:Constituent units
1235:Molecular orbital
1214:
1213:
1194:Constituent units
1154:
1153:
1028:Quantum mechanics
923:978-0-470-03735-5
618:The Chemical Bond
215:quantum mechanics
199:
198:
1501:
1489:Chemical bonding
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1303:
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1287:
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1225:
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1165:
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1146:Exchange-coupled
1048:
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1011:Chemical bonding
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891:10.1038/329491b0
866:
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847:10.1038/329492a0
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798:10.1038/325396d0
768:
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761:
750:10.1038/323699a0
725:
719:
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703:
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678:
677:
660:(7): 1602â1609.
644:Bury, Charles R.
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634:
633:
621:
611:
488:
474:
421:
409:electron density
347:digital computer
283:Matrix Mechanics
260:Gilbert N. Lewis
243:Lewis structures
219:chemical bonding
191:
184:
177:
161:GW approximation
28:
27:
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1185:Lewis structure
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510:basis functions
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396:molecules. The
378:atomic orbitals
370:Lewis structure
355:
327:Charles Coulson
292:
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223:atomic orbitals
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85:Coupled cluster
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1271:Antibonding MO
1268:
1266:Non-bonding MO
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1175:Hybrid orbital
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1044:Types of bonds
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1023:Atomic orbital
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712:Walter Heitler
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502:Main article:
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295:Walter Heitler
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264:Walther Kossel
245:. The chemist
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1453:Pauling Field
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1201:Covalent bond
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1112:5 (quintuple)
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1107:4 (quadruple)
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944:
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933:
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919:
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877:(6139): 491.
876:
872:
865:
857:
853:
848:
843:
839:
835:
832:(6139): 492.
831:
827:
823:
816:
808:
804:
799:
794:
790:
786:
783:(6103): 396.
782:
778:
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759:
755:
751:
747:
743:
739:
736:(6090): 699.
735:
731:
724:
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713:
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699:
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688:
683:
675:
671:
667:
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646:(July 1921).
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629:0-471-90759-6
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440:hybridization
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307:covalent bond
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303:wavefunctions
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1458:4674 Pauling
1367:
1350:
1342:
1339:(1949 paper)
1330:
1324:Publications
1159:
1117:6 (sextuple)
1084:multiplicity
966:. Retrieved
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531:
527:
524:Applications
518:HartreeâFock
507:
449:
435:
425:
394:ground state
365:
361:
358:
356:
341:
339:
330:
311:Fritz London
276:
272:Abegg's rule
236:
206:
200:
39:
15:
1347:(1970 book)
1333:(1939 book)
1051:By symmetry
561:molecules.
483:James Dewar
428:Sigma bonds
321:(1928) and
239:G. N. Lewis
217:to explain
1473:Categories
1261:Bonding MO
1245:MO diagram
1102:3 (triple)
1097:2 (double)
1092:1 (single)
601:References
491:dihydrogen
289:molecule H
256:octet rule
1378:Resonance
1206:Lone pair
1180:Resonance
1068:Delta (ÎŽ)
1058:Sigma (Ï)
674:0002-7863
390:electrons
374:resonance
319:resonance
237:In 1916,
203:chemistry
1361:Concepts
1228:Concepts
1168:Concepts
963:27229870
856:45218186
758:24349360
584:See also
475:orbitals
464:aromatic
460:magnetic
432:Pi bonds
386:probable
359:covalent
287:hydrogen
281:and the
274:(1904).
1420:Related
1399:Founded
1141:Singlet
1136:Triplet
1073:Phi (Ï)
968:25 June
899:4268597
879:Bibcode
834:Bibcode
807:4261220
785:Bibcode
738:Bibcode
470:of the
335:valence
331:Valence
233:History
34:methods
1429:(wife)
1353:(1986)
1063:Pi (Ï)
1013:theory
961:
920:
897:
871:Nature
854:
826:Nature
805:
777:Nature
756:
730:Nature
672:
626:
422:-bond.
353:Theory
895:S2CID
852:S2CID
803:S2CID
754:S2CID
557:and F
549:and F
388:that
1240:LCAO
1128:spin
970:2022
959:PMID
918:ISBN
670:ISSN
624:ISBN
481:and
362:bond
1126:By
1082:By
951:doi
887:doi
875:329
842:doi
830:329
793:doi
781:325
746:doi
734:323
662:doi
201:In
1475::
957:.
947:18
945:.
941:.
893:.
885:.
873:.
850:.
840:.
828:.
824:.
801:.
791:.
779:.
775:.
752:.
744:.
732:.
689:,
668:.
658:43
656:.
650:.
442:.
262:.
205:,
1309:e
1302:t
1295:v
1003:e
996:t
989:v
972:.
953::
926:.
901:.
889::
881::
858:.
844::
836::
809:.
795::
787::
760:.
748::
740::
718:.
676:.
664::
632:.
574:z
570:p
566:s
559:2
555:2
551:2
547:2
542:z
538:p
534:2
487:Ï
473:Ï
436:s
420:Ï
291:2
254:(
190:e
183:t
176:v
25:.
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