化学竞赛杂化.pptVIP

§18.2 Structure of ABn Molecules （Abn分子的结构） 1. AB2 valence electron 6 + 7x2 = 20 H2O, H2S valence electron 8 i. Non linear type(bent) (20 valence electron) ex. OF2 , OCl2, SCl2, TeBr2 O: sp3 hybridization ii. Non linear type(bent) (17~19 valence electron) ex. 18 O3 (valence electron) O: sp2 hybridization + pz O O O .. .. .. pz sp2 orbital pz pz anti-bonding non-bonding bonding Isoelectron analogy: SO2 17 valence electron NO2 19 valence electron ClO2 .. .. iii. Linear type (AB2 16 valence electron) CO2 C: sp hybridization +px +py, Isoelectron analogy : CO2, NO2+, N2O, N3-, COS, BeCl2, HgCl2 iv. Linear type (AB2 22 valence electron) ICl2- XeF2 sp3d hybridization §18.2 Structure of ABn Molecules 2. AB3 i. Trigonal Pyramidal type (8, or 26 valence electron) ex. NH3 , PF3, PCl3, AsCl3 sp3 hybridization ii. Trigonal planar type (6, 24 valence electron) Centric atom B: sp2 hybridization 24 -6 18 -12 6 Isoelectron analogy: AlF3, NO3-, CO32-, SO3, Cl2CO, (H2N)2C=O, Cl2C=S anti-bonding non-bonding bonding For four atom angular type moleculars, forming one bonding, two nonbonding and one antibonding orbitals, in general Example: BH3 ex. BF3, NO3-, CO32-, SO3 sp2 3 sp2 hybrid orbitals each with one electron. This one electron pairs with the hydrogen electron. ii. Trigonal planar type (6, 24 valence electron) ex. ClF3, BrF3, sp3d hybrid orbitals iii. T type (28 valence electron) §18.2 Structure of ABn Molecules 3. AB4 Tetragonal Pyramidal type ex. CH4 , NH4+, CCl3 sp3 hybridization dp-? bond ex. PO4 3-, SO42- dxz pz x x px * First of all, let’s take a look at two theories of bonding * 等性杂化 18.1 Theory of hybrid orbital 杂化轨道理论 分子轨道理论 价键理论 化学键理论 价电子离域 价电子定域在两原子之间或成为孤对电子 每个原子提供一个价电子和一个轨道重叠成键 Each ? bond arises from the overlap of an H1s orbital with one of the O2p orbi