[學科] 關於dipole-dipole interaction

看板Chemistry作者 (憨人)時間11年前 (2012/10/21 13:00), 編輯推噓2(2推 0噓 13→)
留言15則, 3人參與, 最新討論串1/1
小弟在書上看到這樣一段文字 Both van der Waals force and dipole-dipole interaction must be overcome for an alkyl halide to boil. Moreover, as the halogen atom increases in size, these interaction become stronger. 隨著鹵素的原子量變大 van der Waals變強我沒有問題，但是dipole-dipole interaction怎麼會變強呢? 書前面才提到bond dipole moment H3C-F = 1.6D H3C-Cl = 1.5D H3C-Br = 1.4D H3C-I = 1.2D 這我沒有問題，因為就我學到的化學知識 氟的電負度最大，和alkyl之間的鍵結最短，故偶極矩最大 但和原文似乎有矛盾的地方? 懇請各位先進幫忙，謝謝!! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 111.252.155.186
推
10/21 16:33, , 1F
induced-dipole?
10/21 16:33, 1F
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10/21 17:52, , 2F
如果是誘導偶極的話說得通，不過原文就顯得有點囉嗦了
10/21 17:52, 2F
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10/21 17:53, , 3F
van der Waal和induced dipole等於是一樣，寫出一種就好?
10/21 17:53, 3F
推
10/21 20:24, , 4F
分子固有偶極變小但 polarizability 變大....
10/21 20:24, 4F
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10/21 20:25, , 5F
我記得induced-dipole變大是這樣解釋的....
10/21 20:25, 5F
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10/21 21:27, , 6F
我把剩下的原文補完
10/21 21:27, 6F
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10/21 21:27, , 7F
A larger electron cloud means that the van der Waals
10/21 21:27, 7F
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10/21 21:28, , 8F
contact area is greater and the electron cloud's
10/21 21:28, 8F
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10/21 21:29, , 9F
polarizability is also greater. Polarizability
10/21 21:29, 9F
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10/21 21:30, , 10F
indicates low readily an electron cloud can be
10/21 21:30, 10F
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10/21 21:31, , 11F
distorted. The larger the atom, the more loosely it
10/21 21:31, 11F
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10/21 21:32, , 12F
holds the electron in its outermost shell and the
10/21 21:32, 12F
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10/21 21:33, , 13F
more they can be distorted to create a strong induced
10/21 21:33, 13F
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10/21 21:35, , 14F
dipole. 這一段不是在說凡德瓦力變大嗎?
10/21 21:35, 14F
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10/21 21:37, , 15F
但沒有說到dipole-dipole interaction如何變大吧?
10/21 21:37, 15F
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