講義教案成果

如何為分子軌道命名ReviewReviewofatomicorbital(原子軌道CoordinationSymmetryofforceCoordinationSphericalpolarcoordinationWavefunctionSphericalharmonicfunctionYlm(MolecularMolecularOrbitalSymmetryinDiatomic(分子軌道PCoordinationSymmetryofforceCoordinationSymmetryofforceARBZRRaroundthez-axis(關于z-軸旋轉對稱性LCAOfunctions,withsymmetryaboutthe

rA rALCAOfunctions,angularwavel=1,LCAOfunctions,angularwavel=1, TwoTwoatomsarrangedalongz-axis,combinationofforms M.O.NsinBe3NsinAsinBOnenodearoundthez-axis =Node(=0)aroundthez-BondingOrbital 問題如何命名分子軌

1s,2p3d,成鍵軌道()還是反鍵軌道 定義:量子數(shù)H原子中(spH原子中(spd=包含分子軸的節(jié)面 如何確定分子軌道的?Rotationaroundthez-axiswillRotationaroundthez-axiswillchangetheshapeortheelectrondensitydistributionofthediatomicBRRotationaroundthez-axiswillnotchangetheshapeortheelectrondensitydistributionofthediatomicZAZAzationof ponentofangularLz 0,1,2,Notation: functionfunctionNode01==與角度PropertiesandClassificationofLz 0,1,2,Notation:PropertiesPropertiesandClassificationof Realizationofthetwowaveeiei eiei

Degeneracyof1 …PropertiesPropertiesandClassificationofs–Moleculars–MolecularOrbitalsymmetryinDiatomicpx-py-(dxz-(dyz-dz2– (dxy- (dx2-y2-dx2-y2軌道對“g”and“u”Symmetryin(x(x,y,z)(x,(x,y,z)德文gerade偶德文ungerade奇nter(中心反演Inversionabout “ SymmetryinReflectionaboutthenodeplane節(jié)面的鏡面反映 分子軌道的類型(分子軌道的類型(命名σAO以“頭頂頭”方式形成成鍵軌道σgσu，它們都繞鍵軸呈圓柱形對稱，區(qū)別在于有無垂直_于鍵軸的節(jié)_HH2的LUMOσu+=0,關于分子軸無H的HOMO2gπ軌道πu和反鍵軌道πg它們都有一個包含鍵軸的節(jié)面，區(qū)別在π直于鍵軸的節(jié)_乙烯的LUMO:+=1,關于分子軸有1個節(jié)

乙烯的HOMO:δAO以“面對面”方式形成成鍵道δg和反鍵軌道δu，它們都有兩個包_Re2Cl82-中的δ*軌+=2,關于分子軸面有2個節(jié)面Re2Cl82-中的δ軌3.43.4HomonuclearDiatomicReviewofmolecularorbitalinhydrogenmolecule 1 1

1J 1J 1Homonucleardiatomicmolecules(同核雙原子分子H2,O2, =BA=BAMolecularOrbitalsymmetryinMolecularOrbitalsymmetryinDiatomics–px-py-(dxz-(dyz-dz2– (dxy- (dx2-y2-dx2-y221z, 21z, 2s 2 )y,(2 212)x, 2121)y,(2 212)2x, p2)z,(2 212212ABA2sB12A1sB (1s1s)ABAB2ThemosteffectiveatomicorbitalcombinationsindiatomicIsHe2IsHe2astableIsHe2astable12 1sAB12 1sAB (1s1s) AB22He++4.75eV(458

2.5eV(241定義鍵級bondorderBO=（成鍵電子數(shù)-反鍵電子數(shù)鍵 =(N*-

=凈成鍵電子對數(shù)

分子中有不成對電子時表現(xiàn)為順磁性 IsHe2IsHe2astableIsHe2astableAA

(1s1s222 (1s2 B 2He4.75eV(458

2.5eV(241Energylevel 兩個因素兩個因素??? ? ABSequenceforlongbonddiatomicg<EnergylevelO2,2 22Energyleveluu<AABSequenceforshortbonddiatomic

BCNOFE2p-BCNOFE2p-EnergylevelAnalternativewayofunderstandingthedifferentenergylevelBCNOFE2p-The2sand2porbitalsofB,C,NareenergeticallythanthoseofOandF.Sothe2sand2pzmayalsohavelargeoverlaps,whichresul changesinB,C,Ndiatomic

2σu(強反鍵 ππ2pxσ1σu （1（1）B2（5×2=10電子 (1πu) (1πu)特點：無σ鍵，只有π1+π1鍵，BO=1（2）C2：（6×2=12電子 (1πu) (1πu)特點：無σ鍵，只有π+π鍵，BO=2，又因弱反1σu不能完全抵銷強成鍵1σg，故BO=2~3。反磁性（3）N2：（7×2=14電子 (1πu) (1πu)注意注意:上述1(1πu)1通常記作(1πu)2,但電子簡并軌道;而2清楚地看出簡并軌道(1πu)2通常記作(1πu)4.為使初學者暫且用了上述標記特點：σ+π+π，BO=3，反磁性 （4）（4）O2：（8×電子11）KK（σ2s）2(σ*2s）2（σ2pz）KK（σ2s）2(σ*2s）2（σ2pz）2 ）1由于每個π3只相當于半個鍵，故解釋了順磁性由O分 O O O 鍵

鍵長/pm )2 （5）F2：（9×2=18電子GroundGroundstateofneutralandionic2He2doesnotexist,butHe+was24.75eV(4584.75eV(458BondOrder D.E.issmallBondOrder D.E.islarge2However,onlyexistsinflamesoroverheated BondOrder D.E.issmallOnlyexistsinhightemperatureItisparamagnetic,itItisparamagnetic,itisafreeComparisonwithhomonucleardiatomicSymmetryinmoleculesandAttentionRotationaroundz-isstillaquantumInversionaboutthemolecularcenterNo“g”and“u”ReflectionaboutthenodeplanWith“+”and“-”Molecular-orbitalTheoryAlsoAppliestoHeteronuclearDiatomicMolecules異核雙原子分子)對成鍵MO的較大貢獻來自電負性較大的原子對反鍵MO的較大貢獻來自電負性較小的原子 引起的能量降低不顯著Ground Ground 91.7 91.7 6.11 6.11 1.82 根據(jù)能級相近原則，只有

--BO=是名副其實的分子軌道是名副其實的分子軌道其余的基本是F的原子軌道HFVS.“等電子原理 -的分子軌道與N2相似Ground 112.8 11.09Ground 112.8 11.09Ground112.811.090.112 0.112 0.112OCOCCOLookingforthereasonwhyCOisaweakpolar12345C