有机化学英文课件：CH1-Introduction.pptVIP

* boron ???[?b??r?n] * * Ester Functional Group? Amide Functional Group? Carboxylic Acid Functional Group? Bonding Na Cl: Na :Cl: .. .. . . .. .. + - Ionic Bond H. + .H H : H Covalent Bond Lewis Structures H:O:H .. .. H:C:H H H .. .. H . :O: . . :C . . H : O : H . . . . unshared pair :F: B :F: :F: .. .. :N:H H H .. .. :F:B : N:H :F: :F: H H .. .. .. .. .. .. .. .. .. .. .. .. :F:B : N:H :F: :F: H H .. .. .. .. .. .. .. . . + - FORMAL CHARGE Half of the electrons in each bond belong to an atom H : O : N : O : O: .. .. .. .. .. .. .. Nitric Acid HNO3 + _ : = Resonance Structures Resonance hybrid Resonance hybrid 共振论认为一个分子（或离子或自由基）的结构不能用一个经典结构式表述，分子的真实结构是这些极限式的共振杂化体，共振的结果使体系能量降低。 Dipole Moments H - F - Dipole Moment = charge x distance = 4.8 x 10-10 x 10-8 = 4.8 x 10-18 = 4.8 D (Debye) + CH3F Bond Dipole Moment H-F H-Cl H-Br H-I C-F C-Cl C-Br C-I 1.7 1.1 0.8 0.4 1.4 1.5 1.4 1.2 net dipole moment = 0 CCl4 Net Dipole Moment = 1.62 D Summary Functional Groups Ionic Bonds Covalent Bonds Lewis Structures Dipole Moments 1.3 Characteristics of organic compounds 1. Burn ability (flammability) C, H 2. Low melting point 400℃ NaCl800℃. 3. Insoluble in water, soluble in organic solvent. like- dissolves-like 4. Low rate of reactions Intermolecular reaction through molecule collision effective collision 5.complexity of organic reaction. 6. Isomerism 同分异构现象：如：Formula：C2H6O 存在乙醇和甲醚两种同分异构体 ethanol Methyl ether Types of Organic Reaction Radical reaction Ionic reaction Electrophilic reaction Nucleophilic reaction 1.5 Acids and bases in organic chemistry A Bronsted-Lowry acid is a substance that can donate a proton (H+); a Bronsted-Lowry base is a substance that can accept a proton. A Lewis acid is a substance that can accept an electron pair; a Lewis base is a substance that donates an unshared electron pair. e.g. Lewis Base Compounds containing O or N, comparing with C, have lone pair of electron,