南郵材料化學(xué)mc20xx-chapter2-a(存儲(chǔ)版)
【正文】 en bond is formed between two electronegative atoms (A, B). 32 Example Hydrogen bond in H2O 33 Characteristic amp。 High coordination number； High thermal and electronical conductive； ductility。 Nondirectional and unsaturated。 chemical bonds Comparison of five bonds Chemical bonds (primary bonds) Physical bonds (secondary bonds) Ionic bond Van der Waals bond Covalent bond Metallic bond Hydrogen bond 39 type Source Strength Characteristics Properties of pound metallic Coulomb attraction between free electron gas and positive ions core strong Nondirectional and unsaturated, closepacked, high coordination number Good plastic, luster, well electronical and thermal conductive Ionic Coulomb attraction between Cation and anion strongest Nondirectional and unsaturated, high coordination number High melting point, high strength and hardness, low swell, bad plastic, conduct electricity when molten or in solution Comparison of five bonds 40 Type Source Strength Characteristics Properties of pound Covalent sharing of pairs of electrons between atoms stronger Saturated and directional； low coordination number. High melting point and Hardness, Good optical Property, nonconductive Hydrogen Coulomb force of H and atoms with high electronegative weak Van der walls Induction between dipoles in atoms weakest Nondirectional and unsaturated, closepacked High melting point, nonconductive 41 Bonds in actual materials Bonds in the practical materials 42 Interaction and bond energy between atoms ※ Potential Energy Well ※ Calculation of bond energy 43 ——curve of relationship between the total potential energy (E) and distance of atoms. E＝ EA＋ ER EA: electrostatic attractive energy A maEr??a—constant。 High coordination number. High melting point, high strength and hardness, low swell, bad plastic. Ionic pounds conduct electricity when molten or in solution 27 (3) Covalent bond （ 3） Covalent bond A coval
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