分子轨道理论,杂化.pdf

《分子轨道理论,杂化.pdf》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、Chemistry5.12,Lecture#3,2/10/03࣪ᄺ5.12,䆆ᑻ3,2003ᑈ2᳜10᮹໻㒆OutlineIII.ReviewofMolecularOrbitalTheory(ߚᄤ䔼䘧⧚䆎໡д˄䯙䇏㄀Ѡゴ˅ReadChapter2)A.AtomicOrbitals(ॳᄤ䔼䘧(2-1)2-1)B.Sigma-Bonding(³䬂(2-2A)2-2A)C.Pi-Bonding(±䬂(2-2B)2-2B)D.VSEPRTheory(Ӌሖ⬉ᄤᇍѦ᭹⧚䆎2-4(VSEPR))(2-4)IV.Hybridization/L

2、CAOᴖ࣪/ॳᄤ䔼䘧㒓ᗻ㒘ড়（LCAO）A.spHybridization(ᴖ࣪(2-4A)2-4A)B.sp2Hybridization(2-4B)ᴖ࣪(2-4B)C.sp3Hybridization(ᴖ࣪(2-4C)2-4C)1.RotationofEthaneversusEthylene(Э⛋੠Э⛃ᮟ䕀Пᇍ↨(2-3,7,8)2-3,7,8)ProblemSet#1DueTodayby4pmҞ໽ϟज4⚍ϞѸд乬䲚#1ProblemSet#2PostedᏗ㕂д乬#2：ϟ਼ѠϞѸ:DueTuesday(2/18/03)(20

3、03年2月18日)SuggestedProblems:᥼㤤乬Ⳃ˖2-28,29,31,33*Read2-12,13:SurveyofOr䯙䇏᳝ᴎߚᄤ㒉㾜ganicMoleculesIII.MolecularOrbitalTheoryߚᄤ䔼䘧⧚䆎⬉ᄤᰃϔ⾡⊶ʽElectronsAreWaves!TheyExistas3-DStandingWaves(Orbitals).ᅗӀҹϝ㓈偏⊶ⱘᔶᓣᄬ೼(䔼䘧)ॳᄤ䔼䘧：原子中未杂化的轨道(s,p,d)atomicorbitals:unhybridizedorbitalsonanatom(

4、s,p,d)ॳᄤ䔼䘧㒓ᗻ㒘ড়LinearCombina˖⣀ゟⱘ䔼䘧⊶ߑ᭄(䔼䘧)ⳌѦ㒘ড়ᔶ៤њॳᄤⱘᴖ࣪䔼䘧tionofAtomicOrbitals(LCAO):Individualwave(sp,sp2,sp3)ҹঞߚᄤ䔼䘧(σ,σ∗,π,π∗)23functions(orbitals)combinetoformhybridatomicorbitals(sp,sp,sp)andmolecularorbitals(σ,σ*,π,π*)ॳᄤᴖ࣪䔼䘧˖HybridAtomiⳌৠॳᄤⱘॳᄤ䔼䘧㒘ড়cOrbital:Combinati

5、onofatomicorbitalsfromthesameatomߚᄤ䔼䘧˖ϡৠॳᄤⱘ䔼䘧㒘ড়MolecularOrbital:Combinationofatomicorbitalsfromdifferentatoms䔼䘧ᅜᘦConser˖䔼䘧঴ࡴҹৢᔶ៤ᮄ䔼䘧ⱘ᭄ⳂϢ঴ࡴࠡⱘ᭄ⳂⳌৠDŽvationofOrbitals:Whenyouaddorbitalstogether,youalwaysendupwiththesamenumberoforbitalsthatyoustartedwith.1A.AtomicOrbitalsॳ

6、ᄤ䔼䘧•Thes੠p䔼䘧ᰃ᳝ᴎ࣪ড়⠽Ё᳔䞡㽕ⱘ䔼䘧DŽs-andp-orbitalsarethemostimportantinorganiccompounds.•Orbitalpicturesareactuallyelectronprobabilityclouds.䔼䘧೒ᅲ䰙ᰃ⬉ᄤ޴⥛ѥDŽyyyyxxxxzzzzspXpYpZs䔼䘧-orb˖ਜ⧗ᔶߚᏗˈ⬉ᄤ⾏Ḍ䖥ˈऩϔヺোitals:spherical,electronsheldclosetonucleus,onesignp䔼䘧-orb˖ϸ⪷ᓖোˈ⬉ᄤ⾏Ḍ䕗䖰itals:two

7、lobeswithoppositesigns,electronsfurtherfromnucleus•Remember,thesignoftheorbitaldoesnotindicatecharge.ߛ䆄ˈ䔼䘧ⱘℷ䋳োϡҷ㸼⬉㥋DŽᅗাҷ㸼⊶ߑ᭄ⱘヺোˈ៥Ӏৃҹᅮᗻഄ⧚㾷Ў䔼䘧䯈ⱘⳌѦ԰⫼ᰃItrepresentsthesignofthewavefunctionandletsusthink৺᳝߽(៤䬂Ϣড䬂)DŽqualitativelyaboutwhetherorbitalinteractionsareconstructive

8、(bonding)ordestructive(anti-bonding).B.Sigma-Bonding(³䬂σ)•Sigma-bondingorbitalsarecylindricallysymmetricalmolecularorbitals.³៤䬂䔼䘧Ў೚᷅ᔶᇍ⿄ⱘߚᄤ