18.218.2Bonding in Methane andBonding in Methane andOrbital HybridizationOrbital Hybridizationtetrahedraltetrahedralbond angles = 109.5°bond angles = 109.5°bond distances = 110 pmbond distances = 110 pmbut structure seems inconsistent withbut structure seems inconsistent withelectron configuration of carbonelectron configuration of carbonStructure of MethaneStructure of MethaneElectron configuration of carbonElectron configuration of carbon22ss22pponly two unpaired only two unpaired electronselectronsshould form should form !! bonds to only two bonds to only two hydrogen atomshydrogen atomsbonds should be bonds should be at right angles to at right angles to one anotherone another22ss22ppPromote an electron from the 2Promote an electron from the 2s s to the 2to the 2pp orbital orbital spsp33 Orbital Hybridization Orbital Hybridization22ss22pp22pp22ssspsp33 Orbital Hybridization Orbital Hybridization22pp22ssspsp33 Orbital Hybridization Orbital HybridizationMix together (hybridize) the 2Mix together (hybridize) the 2ssorbital and the three 2orbital and the three 2pp orbitals orbitals22pp22ssspsp33 Orbital Hybridization Orbital Hybridization2 2 spsp334 equivalent half-filled4 equivalent half-filledorbitals are consistentorbitals are consistentwith four bonds andwith four bonds andtetrahedral geometrytetrahedral geometryShapes of orbitalsShapes of orbitalsssppNodal properties of orbitalsNodal properties of orbitalssspp++––++Shape of spShape of sp33 hybrid orbitals hybrid orbitalssspp++––++take the take the ss orbital and place it on orbital and place it ontop of the top of the pp orbital orbitalShape of spShape of sp33 hybrid orbitals hybrid orbitalss + ps + p++––++reinforcement of electron wave inreinforcement of electron wave inregions where sign is the sameregions where sign is the samedestructive interference in regions ofdestructive interference in regions ofopposite signopposite signShape of spShape of sp33 hybrid orbitals hybrid orbitalssp sp hybridhybridorbital shown is orbital shown is spsp hybrid hybridanalogous procedure using three analogous procedure using three ss orbitals orbitalsand one and one p p orbital gives orbital gives spsp33 hybrid hybridshape of shape of spsp33 hybrid is similar hybrid is similar++––Shape of spShape of sp33 hybrid orbitals hybrid orbitalssp sp hybridhybridhybrid orbital is not symmetricalhybrid orbital is not symmetricalhigher probability of finding an electron onhigher probability of finding an electron onone side of the nucleus than the otherone side of the nucleus than the otherleads to stronger bondsleads to stronger bonds++––––++––The CThe C——H H !! Bond in Methane Bond in Methanespsp33ssCHHH——C C !!CHgives a gives a !! bond. bond.In-phase overlap of a half-filled 1In-phase overlap of a half-filled 1ss orbital of orbital ofhydrogen with a half-filled hydrogen with a half-filled spsp33 hybrid orbital of hybrid orbital ofcarbon:carbon:++++Justification for Orbital Hybridization Justification for Orbital Hybridization consistent with structure of methaneconsistent with structure of methaneallows for formation of 4 bonds rather than 2allows for formation of 4 bonds rather than 2bonds involving bonds involving spsp3 3 hybrid orbitals are stronger hybrid orbitals are stronger than those involving than those involving ss--s s overlap or overlap or pp--pp overlap overlap18,218,2spsp33 Hybridization Hybridization and Bonding in Ethaneand Bonding in EthaneStructure of EthaneStructure of EthaneCHCH33CHCH33CC22HH66tetrahedral geometry at each carbontetrahedral geometry at each carbonCC——H bond distance = 110 pmH bond distance = 110 pmCC——C bond distance = 153 pmC bond distance = 153 pmIn-phase overlap of half-filled In-phase overlap of half-filled spsp33 hybrid hybridorbital of one carbon with half-filled orbital of one carbon with half-filled spsp33hybrid orbital of another.hybrid orbital of another.Overlap is along Overlap is along internuclear internuclear axis to give a axis to give a !!bond.bond.The CThe C——C C !! Bond in Ethane Bond in EthaneThe CThe C——C C !! Bond in Ethane Bond in EthaneIn-phase overlap of half-filled In-phase overlap of half-filled spsp33 hybrid hybridorbital of one carbon with half-filled orbital of one carbon with half-filled spsp33hybrid orbital of another.hybrid orbital of another.Overlap is along internuclear axis to give a Overlap is along internuclear axis to give a !!bond.bond.18.218.2spsp22 Hybridization Hybridization and Bonding in Ethyleneand Bonding in EthyleneCC22HH44HH22C=CHC=CH22planarplanarbond angles: bond angles: close to 120°close to 120°bond distances: bond distances: CC——H = 110 pmH = 110 pmC=C = 134 pmC=C = 134 pmStructure of EthyleneStructure of Ethylene22ss22ppPromote an electron from the 2Promote an electron from the 2s s to the 2to the 2pp orbital orbital spsp2 2 Orbital HybridizationOrbital Hybridization22ss22pp22pp22ssspsp22 Orbital Hybridization Orbital Hybridization22pp22ssspsp2 2 Orbital HybridizationOrbital HybridizationMix together (hybridize) the 2Mix together (hybridize) the 2ssorbital and two of the three 2orbital and two of the three 2pporbitalsorbitals22pp22ssspsp22 Orbital Hybridization Orbital Hybridization2 2 spsp223 equivalent half-filled3 equivalent half-filledspsp22 hybrid orbitals plus hybrid orbitals plus1 1 pp orbital left orbital leftunhybridizedunhybridizedspsp22 Orbital Hybridization Orbital Hybridization2 2 spsp222 of the 3 2 of the 3 spsp22 orbitals orbitalsare involved in are involved in !! bonds bondsto hydrogens; the otherto hydrogens; the otheris involved in a is involved in a !! bond bondto carbonto carbonppspsp22 Orbital Hybridization Orbital Hybridization2 2 spsp22pp!!!!!!!!!!"" Bonding in Ethylene Bonding in Ethylene2 2 spsp22the unhybridized the unhybridized pp orbital of orbital of carbon is involved in carbon is involved in "" bonding bondingto the other carbon to the other carbon pp"" Bonding in Ethylene Bonding in Ethylene2 2 spsp22ppeach carbon has an unhybridized 2each carbon has an unhybridized 2pp orbital orbitalaxis of orbital is perpendicular to the plane of the axis of orbital is perpendicular to the plane of the !! bonds bonds"" Bonding in Ethylene Bonding in Ethylene2 2 spsp22ppside-by-side overlap of half-filledside-by-side overlap of half-filledpp orbitals gives a orbitals gives a " " bondbonddouble bond in ethylene has adouble bond in ethylene has a!! component and a