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Double and Triple  Covalent Bonds
Double and Triple Covalent Bonds
Published: 2013/10/24
Channel: The Science Classroom
Bonding Models and Lewis Structures: Crash Course Chemistry #24
Bonding Models and Lewis Structures: Crash Course Chemistry #24
Published: 2013/07/30
Channel: CrashCourse
Covalent - Double & Triple Bonds
Covalent - Double & Triple Bonds
Published: 2011/12/16
Channel: tlowthers
SINGLE, DOUBLE, & TRIPLE COVALENT BONDS
SINGLE, DOUBLE, & TRIPLE COVALENT BONDS
Published: 2015/09/09
Channel: Walter Jahn
3.2 Double and Triple Bonds
3.2 Double and Triple Bonds
Published: 2014/03/15
Channel: Ian Stuart
double bond formation
double bond formation
Published: 2011/01/22
Channel: atwilkins5
Lewis structure - double & triple bonds
Lewis structure - double & triple bonds
Published: 2014/03/19
Channel: Sonya Birazian
14.1 sigma and pi bonds (HL)
14.1 sigma and pi bonds (HL)
Published: 2014/11/23
Channel: Mike Sugiyama Jones
Double Bond Pharmaceutical - Life Science-dagen 2017 #PåScen
Double Bond Pharmaceutical - Life Science-dagen 2017 #PåScen
Published: 2017/03/09
Channel: Finwire.tv
Dot structures II: Multiple bonds | Structure and bonding | Organic chemistry | Khan Academy
Dot structures II: Multiple bonds | Structure and bonding | Organic chemistry | Khan Academy
Published: 2013/01/13
Channel: Khan Academy Organic Chemistry
Explaining the lack of rotation of the C=C double bond
Explaining the lack of rotation of the C=C double bond
Published: 2016/01/25
Channel: MaChemGuy
Double Bond Equivalents
Double Bond Equivalents
Published: 2014/10/07
Channel: Caroline Pharr
NMR splitting across a double bond
NMR splitting across a double bond
Published: 2014/11/16
Channel: EleanorCastracane
Double Bond Formation
Double Bond Formation
Published: 2008/10/21
Channel: mtchemers
Degree of Unsaturation (Double Bond Equivalent)
Degree of Unsaturation (Double Bond Equivalent)
Published: 2014/06/02
Channel: Dr. Anil Palve Academy
Covalent Bonding
Covalent Bonding
Published: 2015/11/04
Channel: Smart Learning for All
Conjugated Bonds
Conjugated Bonds
Published: 2014/06/04
Channel: AK LECTURES
Double Bonds and Alkenes
Double Bonds and Alkenes
Published: 2013/04/14
Channel: AK LECTURES
Valence Bond Theory IV: sp2 Hybridization and Double Bonds
Valence Bond Theory IV: sp2 Hybridization and Double Bonds
Published: 2012/03/05
Channel: Ben's Chem Videos
Carbonyl Double Bond
Carbonyl Double Bond
Published: 2014/06/19
Channel: AK LECTURES
Double Bond Pharma business model video 1
Double Bond Pharma business model video 1
Published: 2017/03/29
Channel: Double Bond Pharmaceutical AB
Naming Cis / Trans Double Bonds
Naming Cis / Trans Double Bonds
Published: 2013/09/19
Channel: chemistNATE
Harry Kroto - Bucky Balls and the Carbon-Phosphorus Double Bond
Harry Kroto - Bucky Balls and the Carbon-Phosphorus Double Bond
Published: 2012/12/21
Channel: The Royal Institution
Naming Alkenes - Nomenclature Tutorial for Double Bound Organic Compounds
Naming Alkenes - Nomenclature Tutorial for Double Bound Organic Compounds
Published: 2013/03/02
Channel: Leah4sci
When are Double & Triple Bonds Needed?
When are Double & Triple Bonds Needed?
Published: 2013/12/03
Channel: owigger
Double Bond Equivalence or Degree of unsaturation in Organic Chemistry for IIT/Medical
Double Bond Equivalence or Degree of unsaturation in Organic Chemistry for IIT/Medical
Published: 2012/11/07
Channel: vishwanathchemistry
Why are There Double Bonds in Molecules like CO2?
Why are There Double Bonds in Molecules like CO2?
Published: 2013/04/30
Channel: RogueSpade
VSEPR for ions with double bonds and lone pairs of electrons on the central atom
VSEPR for ions with double bonds and lone pairs of electrons on the central atom
Published: 2014/10/26
Channel: Robyn Raue
Drawing Lewis structures with double bonds
Drawing Lewis structures with double bonds
Published: 2015/04/21
Channel: Trisha Vickrey
How to calculate the double bond equivalence of a molecule
How to calculate the double bond equivalence of a molecule
Published: 2016/10/20
Channel: AnalyticalScienceTutor
Double & Triple Bonds - Snatoms
Double & Triple Bonds - Snatoms
Published: 2016/11/14
Channel: Snatoms
Chemistry - Molecular Structure (37 of 45) Hybridization and the Double Bond
Chemistry - Molecular Structure (37 of 45) Hybridization and the Double Bond
Published: 2014/01/21
Channel: Michel van Biezen
Naming E / Z Double Bonds (Cahn-Ingold-Prelog)
Naming E / Z Double Bonds (Cahn-Ingold-Prelog)
Published: 2013/09/19
Channel: chemistNATE
Single bonds, double bonds, and triple bonds
Single bonds, double bonds, and triple bonds
Published: 2015/04/15
Channel: Clutch Prep
Chem162 Hybridization and Double Bonds (10.5 part 1)
Chem162 Hybridization and Double Bonds (10.5 part 1)
Published: 2014/01/24
Channel: Amy Cully
Covalent Double Bond - A* booster question
Covalent Double Bond - A* booster question
Published: 2016/06/01
Channel: Science and Maths by Primrose Kitten
Naming Alkenes and Alkynes on the same Compound - ENYNE *Error at 3:18*
Naming Alkenes and Alkynes on the same Compound - ENYNE *Error at 3:18*
Published: 2013/03/08
Channel: Leah4sci
Double Bond Pharma - Aktietorget LIVE 5/9-17
Double Bond Pharma - Aktietorget LIVE 5/9-17
Published: 2017/09/05
Channel: Finwire.tv
Sigma (σ) and Pi (π) Bonds - Single, double, and triple bonds
Sigma (σ) and Pi (π) Bonds - Single, double, and triple bonds
Published: 2012/11/02
Channel: Professor Heath's Chemistry Channel
DOUBLE BOND | actual #1 Q&A (AZ)
DOUBLE BOND | actual #1 Q&A (AZ)
Published: 2017/07/31
Channel: Double Bond Pharmaceutical AB
A.8.4 Describe conjugation of double bonds and wavelength of absorption IB Chemistry HL
A.8.4 Describe conjugation of double bonds and wavelength of absorption IB Chemistry HL
Published: 2011/04/10
Channel: Richard Thornley
DOUBLE BOND | actual #6 (Efter sitdown)
DOUBLE BOND | actual #6 (Efter sitdown)
Published: 2017/09/11
Channel: Double Bond Pharmaceutical AB
Double Bond Pharmaceutical
Double Bond Pharmaceutical
Published: 2016/06/21
Channel: Financial Stockholm
Double Bond Teflon® Promo Action by Tecnoquimia
Double Bond Teflon® Promo Action by Tecnoquimia
Published: 2016/06/22
Channel: Tecnoquimia
Difference Between Single & Double Bonds
Difference Between Single & Double Bonds
Published: 2017/05/20
Channel: Ghazi Al Roumi
Trans and Cis (Z and E) Double Bonds
Trans and Cis (Z and E) Double Bonds
Published: 2012/11/02
Channel: Professor Heath's Chemistry Channel
More Nomenclature Problems, rings with double bond and alcohols
More Nomenclature Problems, rings with double bond and alcohols
Published: 2011/09/13
Channel: Maryellen Nerz-Stormes
Conjugated Double Bonds and Color
Conjugated Double Bonds and Color
Published: 2016/03/18
Channel: Andrew Duval
L
L'isomerizzazione del doppio legame
Published: 2017/03/27
Channel: La Chimica per Tutti!
Reducing Alkenes to Alkanes
Reducing Alkenes to Alkanes
Published: 2012/08/09
Channel: chemistNATE
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WIKIPEDIA ARTICLE

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A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that is between two carbon atoms, can be found in alkenes. Many types of double bonds exist between two different elements. For example, in a carbonyl group with a carbon atom and an oxygen atom. Other common double bonds are found in azo compounds (N=N), imines (C=N) and sulfoxides (S=O). In skeletal formula the double bond is drawn as two parallel lines (=) between the two connected atoms; typographically, the equals sign is used for this.[1][2] Double bonds were first introduced in chemical notation by Russian chemist Alexander Butlerov.[citation needed]

Double bonds involving carbon are stronger than single bonds and are also shorter. The bond order is two. Double bonds are also electron-rich, which makes them reactive.

Chemical compounds with double bonds
Ethene structural.svg
Leuckart-Wallach-Reaktion Aceton.svg
Dimethylsulfoxid.svg
Trans-diazene-2D.png
Ethylene
Carbon-carbon
double bond
Acetone
Carbon-oxygen
double bond
Dimethyl sulfoxide
Sulfur-oxygen
double bond
Diazene
Nitrogen-nitrogen
double bond

Double bonds in alkenes[edit]

Geometry of ethylene

The type of bonding can be explained in terms of orbital hybridization. In ethylene each carbon atom has three sp2 orbitals and one p-orbital. The three sp2 orbitals lie in a plane with ~120° angles. The p-orbital is perpendicular to this plane. When the carbon atoms approach each other, two of the sp2 orbitals overlap to form a sigma bond. At the same time, the two p-orbitals approach (again in the same plane) and together they form a pi-bond. For maximum overlap, the p-orbitals have to remain parallel, and, therefore, rotation around the central bond is not possible. This property gives rise to cis-trans isomerism. Double bonds are shorter than single bonds because p-orbital overlap is maximized.

Double bond presentation Double bond presentation
2 sp2 orbitals (total of 3 such orbitals) approach to form a sp2-sp2 sigma bond Two p-orbitals overlap to form a pi-bond in a plane parallel to the sigma plane

With 133 pm, the ethylene C=C bond length is shorter than the C−C length in ethane with 154 pm. The double bond is also stronger, 636 kJ mol−1 versus 368 kJ mol−1 but not twice as much as the pi-bond is weaker than the sigma bond due to less effective pi-overlap.

In an alternative representation, the double bond results from two overlapping sp3 orbitals as in a bent bond.[3]

Types of double bonds between atoms[edit]

C O N S
C alkene carbonyl group imine thioketone, thial
O dioxygen nitroso compound sulfoxide, sulfone, sulfinic acid, sulfonic acid
N azo compound
S disulfur

Variations[edit]

In molecules, with alternating double bonds and single bonds, p-orbital overlap can exist over multiple atoms in a chain, giving rise to a conjugated system. Conjugation can be found in systems such as dienes and enones. In cyclic molecules, conjugation can lead to aromaticity. In cumulenes, two double bonds are adjacent.

Double bonds are common for period 2 elements carbon, nitrogen, and oxygen, and less common with elements of higher periods. Metals, too, can engage in multiple bonding in a metal ligand multiple bond.

Group 14 alkene homologs[edit]

Double bonded compounds, alkene homologs, R2E=ER2 are now known for all of the heavier group 14 elements. Unlike the alkenes these compounds are not planar but adopt twisted and/or trans bent structures. These effects become more pronounced for the heavier elements. The distannene (Me3Si)2CHSn=SnCH(SiMe3)2 has a tin-tin bond length just a little shorter than a single bond, a trans bent structure with pyramidal coordination at each tin atom, and readily dissociates in solution to form (Me3Si)2CHSn: (stannanediyl, a carbene analog). The bonding comprises two weak donor acceptor bonds, the lone pair on each tin atom overlapping with the empty p orbital on the other.[4][5] In contrast, in disilenes each silicon atom has planar coordination but the substituents are twisted so that the molecule as a whole is not planar. In diplumbenes the Pb=Pb bond length can be longer than that of many corresponding single bonds[5] Plumbenes and stannenes generally dissociate in solution into monomers with bond enthalpies that are just a fraction of the corresponding single bonds. Some double bonds plumbenes and stannenes are similar in strength to hydrogen bonds.[4] The Carter-Goddard-Malrieu-Trinquier model can be used to predict the nature of the bonding.[4]

References[edit]

  1. ^ March, Jerry (1985), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (3rd ed.), New York: Wiley, ISBN 0-471-85472-7 .
  2. ^ Organic Chemistry 2nd Ed. John McMurry.
  3. ^ Advanced Organic Chemistry Carey, Francis A., Sundberg, Richard J. 5th ed. 2007.
  4. ^ a b c Power, Philip P. (1999). "π-Bonding and the Lone Pair Effect in Multiple Bonds between Heavier Main Group Elements". Chemical Reviews. 99 (12): 3463–3504. PMID 11849028. doi:10.1021/cr9408989. 
  5. ^ a b Wang, Yuzhong; Robinson, Gregory H. (2009). "Unique homonuclear multiple bonding in main group compounds". Chemical Communications. Royal Society of Chemistry (35): 5201–5213. doi:10.1039/B908048A. (Subscription required (help)). 
  • Pyykkö, Pekka; Riedel, Sebastian; Patzschke, Michael (2005). "Triple-Bond Covalent Radii". Chemistry: A European Journal. 11 (12): 3511–20. PMID 15832398. doi:10.1002/chem.200401299. 

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