The boiling points of the aluminium halides

I would like to ask why the boiling points of the aluminium halides are in the order:

AlF3 >> AlI3 > AlBr3 > AlCl3

1 個解答

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  • 1 十年前
    最愛解答

    你係某某論壇都問過呢個問題,我係埋呢度答多一次

    Al的electronegativity是1.5,Cl是3

    故bonding是partially ionic or partially covalent-->AlCl3 boiling point最低

    F的EN是4.0,delta EN是4-1.5=2.5-->polarizability最強,故boiling point最強

    AlI3大舊個AlBr3,分子size大D,van der Waals' forces大D

    另類解法:

    Since F- is not so polarizable, AlF3 is ionic & has the hightest boiling point(strong electostatic forces)

    As the other halide ions are polarizable,AlCl3,AlBr3&AlI3 possess high covalent character & are similar to simple molecular substances. As the strength of can der Waals' forces increases with the molecular sizes, the strengths of van der Waals' forces are in the order of AlI3 > AlBr3 > AlCl3

    資料來源: 自己+少少書本上
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