186:
678:
198:
135:
672:
172:), there are two such 3c-2e bonds: two H atoms bridge the two B atoms, leaving two additional H atoms in ordinary B−H bonds on each B. As a result, the molecule achieves stability since each B participates in a total of four bonds and all bonding molecular orbitals are filled, although two of the four bonds are 3-center B−H−B bonds. The reported
684:
56:-bonding. The two electrons go into the bonding orbital, resulting in a net bonding effect and constituting a chemical bond among all three atoms. In many common bonds of this type, the bonding orbital is shifted towards two of the three atoms instead of being spread equally among all three. Example molecules with 3c–2e bonds are the
271:
occur through three-center bond transition states. Because the three center bond structures have about the same energy as carbocations, there is generally virtually no activation energy for these rearrangements so they occur with extraordinarily high rates.
421:
Arrowsmith, M; Braunschweig, H.; Celik, M.A.; Dellermann, T.; Dewhurst, R.D.; Ewing, W.C.; Hammond, K.; Kramer, T.; Krummenacher, I.; Mies, J.; Radacki, K.; and
Schuster, J.K. (2016). "Neutral zero-valent s-block complexes with strong multiple bonding".
345:
I. Mayer (1989). "Bond orders in three-centre bonds: an analytical investigation into the electronic structure of diborane and the three-centre four-electron bonds of hypervalent sulphur".
257:
The first stable subvalent Be complex ever observed contains a three-center two-electron π-bond that consists of donor-acceptor interactions over the C-Be-C core of a Be(0)-carbene adduct.
185:
771:
465:
153:
3-center-2-electron bond is formed when a boron atom shares electrons with a B−H bond on another boron atom. The two electrons (corresponding to one bond) in a
209:
Three-center, two-electron bonding is pervasive in organotransition metal chemistry. A celebrated family of compounds featuring such interactions as called
889:
816:
497:
128:
110:
176:
for each B−H interaction in a bridge is 0.5, so that the bridging B−H−B bonds are weaker and longer than the terminal B−H bonds, as shown by the
202:
751:
736:
560:
315:
587:
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347:
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127:. These molecules derive their stability from having a completely filled set of bonding molecular orbitals as outlined by
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have three-center two-electron bonds. Perhaps the best known and studied structure of this sort is the
97:). In these two structures, the three atoms in each 3c-2e bond form an angular geometry, leading to a
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Nikonov, G. I. (2005). "Recent advances in nonclassical interligand SiH interactions".
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bonding molecular orbital are spread out across three internuclear spaces.
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Electron-deficient chemical bond where three atoms share two electrons
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143:
683:
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described by the polyhedral skeletal electron pair theory, such as
475:
249:; another name for asymmetrical three-center two-electron bonds.
115:
An extended version of the 3c–2e bond model features heavily in
33:
479:
149:
is unstable since the boron atom has an empty p-orbital. A
241:
in bridging positions. This type of bond also occurs in
205:, examples feature three-center two-electron bonding.
852:
829:
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245:compounds, where it is sometimes referred to as
138:Resonance structures of 3c-2e bond in diborane.
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8:
464:: CS1 maint: multiple names: authors list (
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890:Polyhedral skeletal electron pair theory
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111:Polyhedral skeletal electron pair theory
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457:
23:three-center two-electron (3c–2e) bond
221:This bonding pattern is also seen in
7:
237:with the carbon atoms of two of the
14:
203:transition metal silane complexes
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676:
670:
184:
316:Three-center four-electron bond
348:Journal of Molecular Structure
1:
408:10.1016/s0065-3055(05)53006-5
384:, 2nd ed. (Wiley 1987), p.113
361:10.1016/0166-1280(89)87037-X
180:in the structural diagram.
40:. The combination of three
934:
588:Metal–ligand multiple bond
193:Transition metal complexes
108:
668:
382:Basic Inorganic Chemistry
225:, which forms a dimer Al
269:rearrangement reactions
206:
139:
105:Boranes and carboranes
200:
137:
109:Further information:
578:Coordinate (dipolar)
396:Adv. Organomet. Chem
752:C–H···O interaction
534:Electron deficiency
436:2016NatCh...8..890A
48:: one bonding, one
737:Resonance-assisted
444:10.1038/nchem.2542
380:and Paul L. Gaus,
378:Geoffrey Wilkinson
326:Dihydrogen complex
321:2-Norbornyl cation
304:2-Norbornyl cation
223:trimethylaluminium
207:
140:
58:trihydrogen cation
52:-bonding, and one
46:molecular orbitals
27:electron-deficient
903:
902:
854:Electron counting
825:
824:
714:London dispersion
666:
665:
643:Metal aromaticity
211:agostic complexes
117:cluster compounds
923:
916:Chemical bonding
895:Jemmis mno rules
747:Dihydrogen bonds
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608:Hyperconjugation
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42:atomic orbitals
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515:Intramolecular
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430:(9): 890–894.
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868:Hückel's rule
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797:Intercalation
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787:Metallophilic
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704:Van der Waals
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239:methyl groups
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30:chemical bond
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873:Baird's rule
593:Charge-shift
556:Hypervalence
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460:cite journal
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261:Carbocations
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220:
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201:One of many
178:bond lengths
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154:
150:
142:The monomer
141:
129:Wade's rules
114:
53:
49:
32:where three
22:
20:
18:
863:Aromaticity
839:Heterolysis
817:Salt bridge
762:Noncovalent
732:Low-barrier
613:Aromaticity
603:Conjugation
583:Pi backbond
402:: 217–309.
266:Carbocation
44:form three
791:aurophilic
772:Mechanical
332:References
174:bond order
125:carboranes
36:share two
883:spherical
844:Homolysis
807:Cation–pi
782:Chalcogen
742:Symmetric
598:Hapticity
355:: 43–52.
253:Beryllium
99:bent bond
38:electrons
910:Category
812:Anion–pi
802:Stacking
724:Hydrogen
635:Metallic
526:Covalent
518:(strong)
452:27334631
310:See also
280:ethanium
278:such as
162:diborane
74:diborane
777:Halogen
623:bicyclo
568:Agostic
432:Bibcode
121:boranes
878:Möbius
706:forces
696:(weak)
450:
243:carbon
72:) and
25:is an
856:rules
765:other
653:Ionic
561:3c–4e
549:8c–2e
544:4c–2e
539:3c–2e
155:B−H−B
151:B−H−B
34:atoms
618:homo
573:Bent
466:link
448:PMID
123:and
54:anti
440:doi
404:doi
357:doi
353:186
229:(CH
160:In
50:non
912::
462:}}
458:{{
446:.
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400:53
398:.
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351:.
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164:(B
144:BH
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21:A
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789:(
499:e
492:t
485:v
468:)
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442::
434::
428:8
410:.
406::
363:.
359::
297:7
292:H
288:2
283:C
235:6
233:)
231:3
227:2
170:6
168:H
166:2
146:3
92:6
87:H
83:2
78:B
76:(
67:3
62:H
60:(
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