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1、2018/10/19,1,Chapter 6 Molecular structure and Bonding,物质结构（2）,1. How the shapes of simple molecules can be described and predicted,2. Examin why molecules have the shapes they do and look more closely at how atoms use their electrons to form bonds.,2018/10/19,2,空间构型,分子,原子,化学键,共价键,离子键,金属键,杂化轨道理论,VSE
2、PR,键的极性,物质,分子间作用力,分子的极性,Atomic orbital,Electron,Function,偶极矩,2018/10/19,3,1927年， Heitler W 和 London F., 揭示共价键本质,Pauling L 和 Slater JC ，现代价键理论,1932年， Muiliken RS 和 Hund F ，分子轨道理论,1931年，Pauling L ，杂化轨道理论,1954年，Pauling L ，Nobel prize,1966年， Muiliken RS, Nobel prize,1916年， Kossel, 离子键,1923年， Lewis, 共价键,
3、原子的价电子理论,2018/10/19,4,6.1 Molecular Geometries- Lewis Structures: The octet rule- The VSEPR model,6.2 Covalent Bonding - Valance-bond theory- Hybrid Orbitals,6.3 Molecular orbital theory- The Hydrogen molecules- Molecular orbitals for second-period diatomic molecules,2018/10/19,5,Lewis structures gi
4、ve atomic connectivity,6.1 Molecular Geometries,bonding pair of e-,lone pair of e-,Octet Rule: Each atom shares electrons with neighboring atoms to achieve a total of 8 valence electrons.,- Lewis Structures :The octet rule,2018/10/19,6,Molecular Shapes,Bond Parameter,键长(bond length),键角(bond angle),分
5、子的空间构型,2018/10/19,7,ABn,2018/10/19,8,Valence Shell Electron Pair Repulsion (VSEPR) theory,bonding pairs of electrons (bp),lone pairs ( lp ),lplp,lpbp,bpbp,The electrons adopt an arrangement in space to minimize e-e- repulsion.,斥力大小的顺序：,bonding pair of e-,lone pair of e-,- The VSEPR model,Sigma 键电子对,
6、2018/10/19,9,2018/10/19,10,Predicting Molecular Geometries,确定中心原子价层e总数及e对数,中心原子的价e对按斥力大小顺序，空间排布应取斥力最小的排布方式，e对尽可能远离且呈对称结构,draw,count,arrange,中心原子,配位原子,族序数,键合电子,孤对电子,主族元素,2018/10/19,11,2018/10/19,12,2018/10/19,13,2018/10/19,14,ClF3,分子构型：T字型,电子构型与分子构型不一致,电子数为5时，孤对总是尽先处于三角双锥的腰部位置,location of the lone pa
7、irs,2018/10/19,15,The VSEPR Model,Molecules with Expanded Valence Shells,2018/10/19,16,判断 BF3及NF3的价层电子对构型及分子构型。 （Give the electron-pair geometry and the molecular geometry of BF3 and NF3.）,2018/10/19,17,-Lewis structures and VSEPR do not explain why a bond forms.,2018/10/19,18,6.2 Covalent Bonding,价
8、键理论,杂化轨道理论,Valence bond theory (VB),Hybrid orbital theory,2018/10/19,19,Walther Kossel 1916,离子键 （ionic bond）,2018/10/19,20,1923年， Lewis GN, Irving Langmuir, 经典的共价键理论，,Less than octet - ex: BF3 More than octet - ex: PCl5,共价健(Covalent bond),2018/10/19,21,attractive forces,repulsive forces,Bond Length,
9、1927年， Heitler W 和 London F., 揭示共价键本质,2018/10/19,22,Covalent Bonding and Orbital Overlap,2018/10/19,23,共价键的本质,本质上是电性的。 但它不同于一般的静电作用，它是两原子核共同对核间电子云密集区的吸引。,2018/10/19,24,将H2的研究结果推广至其它双原子分子和多原子分子,价键理论,自旋相反的单电子配对,自旋相反的单电子配对后，不能再和其它原子中的单电子配对，形成共价键的数目与该原子中单电子数目相同。,饱和性,共价键的形成尽可能沿着原子轨道最大重叠的方向进行，即原子轨道最大重叠原理。
10、,方向性,2018/10/19,25,共价键类型,键,键,s-s,s-px,px-px,键轴（internuclear axis）,x,x,轨道的重叠部分沿键轴呈圆柱形对称分布,py-py,pz-pz,轨道的重叠部分垂直于键轴并呈镜面反对称分布,2018/10/19,26,double bonds,triple bonds,Multiple Bonds,共价键类型,配位健（Coordination covalent bond）,2018/10/19,27,键参数 (Bond Parameters),键能(bond energy),键长(bond length),键角(bond angle),键
11、的极性 (Polarity of bond),分子的空间构型,电负性,极性共价键 (Polar covalent bond),非极性共价键 (nonpolar covalent bond),2018/10/19,28,e- rich,e- poor,indicates a bond dipole,2018/10/19,29,Bond Type and DEN,Equal sharing of e- pair,Unequal sharing of e- pair,(Nearly) complete e- transfer,2018/10/19,30,分子的极性(Polarity of molec
12、ules),the charge distribution in a molecule,双原子分子的极性（The polarity diatomic molecule）,Polar Molecule,化学键的极性,多原子分子的极性 (The polarity of Polyatomic molecules),化学键的极性,分子的空间构型,2018/10/19,31,2018/10/19,32,偶极矩() (dipole moment):,The degree of polarity,A quantitative measure of the degree of charge separatio
13、n in a molecule.,2018/10/19,33,Relating Dipole Moment and Molecular Geometry,Each of the following molecules has a nonzero dipole moment. Select the molecular geometry that is consistent with this information. Explain your reasoning.,SO2 linear, bent PH3 trigonal planar, trigonal pyramidal,2018/10/1
14、9,34,Permanent dipole moment,Induced dipole moment,分子的极化(Molecular polarization),2018/10/19,35,Problem:,1954年，Pauling L ，Nobel prize,1931年，Pauling L ，杂化轨道理论,2018/10/19,36,杂化轨道理论 (Hybrid orbital theory),General principles of Hybrid orbital theory,Types of Hybrid orbitals,Apply VSEPR Theory and Determ
15、ine Hybridization,2018/10/19,37,General principles of Hybrid orbital theory,键,s-s,s-px,px-px,SP3 - s,2018/10/19,38,-成键过程中，同一原子中的几个能量相近的原子轨道重新 组合成数目相等、能量相同、方向一定的新的原子轨道。,-杂化轨道比原来的原子轨道的成键能力强。,-杂化轨道具有确定的方向，轨道之间在空间上采取最大角度分布。,Valence Bond Theory - atoms form bonds by overlapping atomic and/or hybrid orbit
16、als,2018/10/19,39,SP3 杂化,2018/10/19,40,SP3 杂化,2018/10/19,41,等性杂化轨道(Equivalent hybrid orbital),不等性杂化轨道( Unequivalent hybrid orbital),2018/10/19,42,sp Hybridization,VSEPR Theory,Be: 1s22s2,Be: 1s22s12p1,hybridization,2018/10/19,43,sp杂化,键,s-s,s-px,px-px,SP3 - p,SP - p,2018/10/19,44,BF3 - trigonal planar,sp2 Hybridization,VSEPR Theory,2018/10/19,45,sp2杂化,键,s-s,s-px,px-px,SP3 - p,SP - p,SP2 - p,2018/10/19,46,sp3d Hybridization,VSEPR Theory,
