羥基(hydroxyl)和氫氧化物(hydroxide)的區別
羥基和氫氧化物這兩個詞聽起來非常相似，因為它們都有兩個相似的原子，氧（O=16）和氫（H=1）。氫氧化物是一種帶單電荷的負離子，羥基不是以自由形式存在的，而是另一分子或離子的一部分。氫氧化離子比分子中的羥基更活潑。這就是羥基和氫氧化物之間的關鍵區別。
什麼是羥基(hydroxyl)？
Hydroxyl is a neutral compound and it is the corresponding electrically neutral compound of hydroxide ion. The free form of hydroxyl (•HO) is a radical and when it is bonded covalently to other molecules it is denoted as the hydroxyl (–OH) group. Hydroxyl groups can act as nucleophiles and hydroxyl radical is used as a catalyst in organic chemistry. Hydroxyl groups are not highly reactive as the other nucleophiles. However, they are the facilitators in the formation of strong intramolecular forces called ‘hydrogen bonds’.
什麼是氫氧化物(hydroxide)？
Hydroxide is a diatomic anion which contains an oxygen atom and a hydrogen atom. The bond between oxygen and hydrogen atom is covalent and its chemical formula is OH–. Self-ionization of water produces hydroxyl i*** and therefore hydroxyl i*** are a natural part in the water. Hydroxide i*** are utilized as a base, a ligand, a nucleophile and a catalyst in chemical reacti***. In addition, hydrogen i*** produce salts with metal cati*** and most of them dissociate in aqueous soluti***, releasing solvated hydroxide i***. Many inorganic chemical substances contain the term “hydroxide” in their name, but they are not ionic and they are covalent compounds which contain hydroxyl groups.
羥基(hydroxyl)和氫氧化物(hydroxide)的區別
結構：
羥基：羥基是一種電中性化合物，有兩種形式，自由基和共價結合形式。
羥基自由基與分子共價鍵合
氫氧化物：氫氧化物是帶負電的離子，負電荷在氧上原子屬性:
羥基：羥基存在於許多有機化合物中；醇、羧酸和含糖的羥基。含有羥基的化合物，如水、醇和羧酸可以很容易地脫質子化。此外，這些羥基參與氫鍵的形成。氫鍵幫助分子粘在一起，這就導致擁有更高的沸點和熔點。一般來說，有機化合物的水溶性較差；當這些分子含有兩個或兩個以上的羥基時，它們就變得微溶於水。
氫氧化物：大多數含有氫氧化物的化學物質都被認為具有很強的腐蝕性，有些則非常具有腐蝕性有害。什麼時候這些化學物質溶於水，氫氧化物離子起著難以置信的強鹼作用。由於氫氧化物離子帶負電荷，它通常與帶正電荷的離子結合。
一些分子中含有氫氧化物基團的離子化合物能很好地溶解在水中；例如氫氧化鈉（NaOH）和氫氧化鉀（KOH）等腐蝕性鹼。然而，其他一些含氫氧化物的離子化合物在水中稍不溶；例如氫氧化銅[Cu（OH）2-亮藍色]和鐵（II）氫氧化物[Fe（OH）2-棕色]。
反應性：
羥基：與羥基相比，羥基的反應性較小。但是，羥基很容易形成氫鍵，有助於使分子更易溶於水。
然而，羥基自由基具有很高的活性，在有機化學反應中非常有用。
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