107:
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1039:
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40:
173:
p-density) makes it possible to reduce the bond angles to 60°. At the same time, the carbon-to-hydrogen bonds gain more s-character, which shortens them. In cyclopropane, the maximum electron density between two carbon atoms does not correspond to the internuclear axis, hence the name
204:
is a larger ring, but still has bent bonds. In this molecule, the carbon bond angles are 90° for the planar conformation and 88° for the puckered one. Unlike in cyclopropane, the C–C bond lengths actually increase rather than decrease; this is mainly due to 1,3-nonbonded
369:, the C–F bond gains p-orbital character leading to high s-character in the C–H bonds, and H–C–H bond angles approaching those of sp orbitals – e.g. 120° – leaving less for the F–C–H bond angle. The difference is again explained in terms of bent bonds.
344:
concluded that "although a conclusive statement cannot be made on the basis of the currently available information, it seems likely that we can continue to consider the σ/π and bent-bond descriptions of ethylene to be equivalent."
580:
Allen, Frank H.; Kennard, Olga; Watson, David G.; Brammer, Lee; Orpen, A. Guy; Taylor, Robin (1987). "Tables of bond lengths determined by X-ray and neutron diffraction. Part 1. Bond lengths in organic compounds".
611:(1931). "The nature of the chemical bond. Application of results obtained from the quantum mechanics and from a theory of paramagnetic susceptibility to the structure of molecules".
225:
in which cyclopropane is described as a carbon sp sigma bonding and in-plane pi bonding system. Critics of the Walsh orbital theory argue that this model does not represent the
187:
1138:
546:
17:
837:
365:
F), for instance, the experimental F–C–H bond angle is 109°, which is greater than the calculated value. This is because according to
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1183:
864:
238:
229:
of cyclopropane as it cannot be transformed into the localized or fully delocalized descriptions via a unitary transformation.
818:
349:
goes further in a 2010 textbook, noting that "the overall distribution of electrons is exactly the same" in the two models.
255:
proposed that the double bond results from two equivalent tetrahedral orbitals from each atom, which later came to be called
275:. The Hückel representation is the better-known one, and it is the one found in most textbooks since the late-20th century.
1178:
529:
1103:
927:
1118:
954:
915:
905:
910:
857:
407:
Burnelle, Louis; Kaufmann, Joyce J. (1965). "Molecular
Orbitals of Diborane in Terms of a Gaussian Basis".
554:
31:
1282:
1173:
1163:
1153:
1128:
1098:
90:) or as a representation of double or triple bonds within a compound that is an alternative to the
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1205:
1108:
1080:
850:
279:
1249:
1210:
808:
804:
346:
119:
1244:
376:, explaining the preference for gauche conformations in certain substituted alkanes and the
78:
or configuration resembling a similar "bent" structure within small ring molecules, such as
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8:
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127:
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Both models represent the same total electron density, with the orbitals related by a
122:
state of two atoms making up a chemical bond are modified with increased or decreased
1220:
1009:
969:
959:
814:
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341:
183:
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209:. In terms of reactivity, cyclobutane is relatively inert and behaves like ordinary
1261:
1001:
974:
783:
742:
695:
656:
639:
Wintner, Claude E. (1987). "Stereoelectronic effects, tau bonds, and Cram's rule".
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131:
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149:
In these compounds, it is not possible for the carbon atoms to assume the 109.5°
675:
264:
1148:
949:
723:"The Theory of the Structure of Ethylene and a Note on the Structure of Ethane"
366:
357:
The bent bond theory can also explain other phenomena in organic molecules. In
190:
is outside the line of centers between the two carbon atoms. The carbon–carbon
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764:"The Theory of the Stability of the Benzene Ring and Related Compounds"
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385:
268:
153:
with standard sp hybridization. Increasing the p-character to sp (i.e.
150:
91:
39:
660:
506:
467:
428:
964:
195:
143:
123:
547:"Bonding Properties of Cyclopropane and Their Chemical Consequences"
1038:
267:
proposed a representation of the double bond as a combination of a
110:
A humorously literal depiction of the banana bonds in cyclopropane
842:
272:
139:
95:
243:
Two different explanations for the nature of double and triple
210:
71:
1050:
579:
282:. We can construct the two equivalent bent bond orbitals
182:
is 104°. This bending can be observed experimentally by
30:
This article is about chemistry. For other uses, see
194:
are shorter than in a regular alkane bond: 151
813:(Reference ed.). London: Wiley. p. 61.
810:Molecular Orbitals and Organic Chemical Reactions
74:. The term itself is a general representation of
1274:
678:(1930). "Zur Quantentheorie der Doppelbindung".
406:
126:character in order to accommodate a particular
858:
519:
384:associated with some unusually stable alkene
221:An alternative model utilizes semi-localized
442:Klessinger, Martin (1967). "Triple Bond in N
326:π for an appropriate choice of coefficients
493:(1996). "Bent Bonds in Organic Compounds".
865:
851:
544:
441:
232:
70:with a geometry somewhat reminiscent of a
27:Type of covalent bond in organic chemistry
787:
746:
186:of certain cyclopropane derivatives: the
101:
1257:Polyhedral skeletal electron pair theory
485:
483:
481:
479:
477:
105:
43:One of the first bent bond theories for
38:
803:
638:
607:
14:
1275:
761:
720:
674:
601:
520:Carey, F. A.; Sundberg, R. J. (1985).
489:
372:Bent bonds also come into play in the
251:molecules were proposed in the 1930s.
239:Sigma-pi and equivalent-orbital models
216:
846:
474:
352:
47:was the Coulson-Moffitt model (1947).
130:. Bent bonds are found in strained
24:
872:
25:
1294:
831:
114:Bent bonds are a special type of
1049:
1043:
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290:' by taking linear combinations
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583:J. Chem. Soc., Perkin Trans. 2
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1:
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555:Angew. Chem. Int. Ed. Engl.
10:
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955:Metal–ligand multiple bond
545:De Meijere, Armin (1979).
522:Advanced Organic Chemistry
236:
32:Bent bond (disambiguation)
29:
18:Strained organic compounds
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1196:
1127:
1089:
1069:
1058:
1035:
1018:
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233:Double and triple bonds
178:. In cyclopropane, the
789:10.1098/rspa.1934.0151
762:Penney, W. G. (1934).
748:10.1098/rspa.1934.0041
721:Penney, W. G. (1934).
567:10.1002/anie.197908093
280:unitary transformation
118:in which the ordinary
111:
102:Small cyclic molecules
48:
237:Further information:
109:
42:
945:Coordinate (dipolar)
595:10.1039/P298700000S1
340:. In a 1996 review,
198:versus 153 pm.
1119:C–H···O interaction
901:Electron deficiency
780:1934RSPSA.146..223P
739:1934RSPSA.144..166P
692:1930ZPhy...60..423H
653:1987JChEd..64..587W
625:10.1021/ja01355a027
460:1967JChPh..46.3261K
421:1965JChPh..43.3540B
217:Walsh orbital model
188:deformation density
1104:Resonance-assisted
700:10.1007/BF01341254
491:Wiberg, Kenneth B.
353:Other applications
180:interorbital angle
128:molecular geometry
112:
59:, also known as a
49:
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1221:Electron counting
1192:
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1081:London dispersion
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1032:
1010:Metal aromaticity
820:978-0-470-74658-5
661:10.1021/ed064p587
507:10.1021/ar950207a
468:10.1063/1.1841197
429:10.1063/1.1696513
342:Kenneth B. Wiberg
184:X-ray diffraction
132:organic compounds
53:organic chemistry
16:(Redirected from
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1283:Chemical bonding
1262:Jemmis mno rules
1114:Dihydrogen bonds
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774:(856): 223–238.
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686:(7–8): 423–456.
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609:Pauling, Linus
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589:(12): S1–S19.
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68:chemical bond
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33:
19:
1240:Baird's rule
960:Charge-shift
939:
923:Hypervalence
809:
805:Fleming, Ian
799:
771:
768:Proc. R. Soc
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727:Proc. R. Soc
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265:Erich Hückel
260:
257:banana bonds
256:
242:
227:ground state
220:
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192:bond lengths
179:
175:
148:
136:cyclopropane
113:
80:cyclopropane
60:
56:
50:
45:cyclopropane
36:
1230:Aromaticity
1206:Heterolysis
1184:Salt bridge
1129:Noncovalent
1099:Low-barrier
980:Aromaticity
970:Conjugation
950:Pi backbond
367:Bent's rule
347:Ian Fleming
202:Cyclobutane
151:bond angles
61:banana bond
1158:aurophilic
1139:Mechanical
676:Hückel, E.
647:(7): 587.
395:References
269:sigma bond
1250:spherical
1211:Homolysis
1174:Cation–pi
1149:Chalcogen
1109:Symmetric
965:Hapticity
708:120342054
446:and CO".
261:tau bonds
176:bent bond
144:aziridine
124:s-orbital
57:bent bond
1277:Category
1179:Anion–pi
1169:Stacking
1091:Hydrogen
1002:Metallic
893:Covalent
885:(strong)
807:(2010).
134:such as
65:covalent
1144:Halogen
990:bicyclo
935:Agostic
776:Bibcode
735:Bibcode
688:Bibcode
680:Z. Phys
649:Bibcode
456:Bibcode
417:Bibcode
389:isomers
378:alkene
273:pi bond
271:plus a
249:organic
211:alkanes
168:⁄
158:⁄
140:oxirane
98:model.
96:pi bond
1245:Möbius
1073:forces
1063:(weak)
817:
706:
528:
382:effect
308:π and
72:banana
1223:rules
1132:other
1020:Ionic
928:3c–4e
916:8c–2e
911:4c–2e
906:3c–2e
704:S2CID
550:(PDF)
92:sigma
985:homo
940:Bent
815:ISBN
772:A146
731:A144
587:1987
526:ISBN
333:and
319:σ –
312:' =
301:σ +
286:and
142:and
94:and
55:, a
784:doi
743:doi
696:doi
657:doi
621:doi
591:doi
563:doi
503:doi
464:doi
425:doi
387:cis
380:cis
361:(CH
259:or
247:in
51:In
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391:.
294:=
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196:pm
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82:(C
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866:e
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335:c
331:1
328:c
324:2
321:c
317:1
314:c
310:h
306:2
303:c
299:1
296:c
292:h
288:h
284:h
170:6
166:5
160:6
156:1
88:6
86:H
84:3
34:.
20:)
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