三氯化鋁危險(xiǎn)特性：極易水解，遇水反應(yīng)發(fā)熱放出有毒的腐蝕性氣體（氯化氫）。
Hazard characteristics of aluminum trichloride: it is easy to hydrolyze, react with water, generate heat, and release toxic corrosive gas (hydrogen chloride).
它的蒸氣是締合的雙分子。氯和強(qiáng)熱的金屬鋁反應(yīng)即得無(wú)水氯化鋁。溶于許多有機(jī)溶劑。在空氣中極易吸取水分而發(fā)生煙霧。水溶液呈酸性。水溶液中析出的晶體是六水合物而不能得到無(wú)水氯化鋁（AlCl3），因?yàn)檫M(jìn)一步蒸干會(huì)導(dǎo)致鋁離子完全水解，因此后者只能通過(guò)鋁和氯氣直接反應(yīng)獲得。無(wú)水氯化鋁在石油工業(yè)中及其他某些有機(jī)合成反應(yīng)中用作催化劑。
Its vapor is a bimolecular association. Anhydrous aluminum chloride is obtained by the reaction of chlorine with strong heat metal aluminum. Soluble in many organic solvents. It is very easy to absorb moisture in the air and produce smoke. The aqueous solution is acidic. The crystal precipitated from aqueous solution is hexahydrate, but anhydrous aluminum chloride (AlCl3) can not be obtained, because further evaporation will lead to complete hydrolysis of aluminum ions, so the latter can only be obtained by direct reaction of aluminum and chlorine. Anhydrous aluminum chloride is used as a catalyst in petroleum industry and some other organic synthesis reactions.
三氯化鋁的價(jià)鍵性質(zhì)：鋁為sp3軌道雜化，分子中存在橋鍵，和乙硼烷的結(jié)構(gòu)相似（AlCl3的分子式其實(shí)是Al2Cl6），這樣可以讓Al達(dá)到八電子穩(wěn)定結(jié)構(gòu)。但Al2Cl6可以和路易斯堿作用，例如Al2Cl6+2Cl-→2[AlCl4]-。產(chǎn)物相當(dāng)于AlCl3單體和路易斯堿的加合物，因此氯化鋁仍然是一種非常好的路易斯酸（路易斯酸性較強(qiáng)），利用其性質(zhì)常用來(lái)做有機(jī)反應(yīng)的催化劑。
The valence bond properties of aluminum trichloride: aluminum is SP3 orbital hybrid, and there is bridge bond in the molecule, which is similar to the structure of ethylborane (the molecular formula of AlCl3 is al2cl6), so that Al can reach the eight electron stable structure. However, al2cl6 can interact with Lewis bases, such as al2cl6 + 2Cl - → 2 [alcl4] -. The product is equivalent to the adduct of AlCl3 monomer and Lewis base, so aluminum chloride is still a very good Lewis acid (strong Lewis acid), which is often used as a catalyst for organic reactions.
需要注意一點(diǎn)的是，雖然三氯化鋁是由金屬原子和非金屬原子化合而成，但氯化鋁（AlCl3）并不屬于離子化合物，而屬于共價(jià)化合物。這是中學(xué)化學(xué)中一個(gè)典型的由金屬和活潑非金屬元素組成的共價(jià)化合物。因?yàn)殇X為sp3軌道雜化，分子中存在橋鍵，和乙硼烷的結(jié)構(gòu)相似（AlCl3的分子式其實(shí)是Al2Cl6），這樣可以讓Al達(dá)到八電子穩(wěn)定結(jié)構(gòu)。所以AlCl3是共價(jià)化合物，不是離子化合物！
It should be noted that aluminum chloride (AlCl3) is not an ionic compound, but a covalent compound, although it is composed of metal atoms and non-metal atoms. This is a typical covalent compound composed of metal and active nonmetal elements in middle school chemistry. Because aluminum is SP3 orbital hybrid, there is a bridge bond in the molecule, which is similar to the structure of borane (the molecular formula of AlCl3 is al2cl6), so that Al can reach the eight electron stable structure. So AlCl3 is a covalent compound, not an ionic compound!
