Aluminum chloride, or anhydrous aluminum trichloride, aluminum trichloride, has the chemical formula AlCl3, which is a compound of chlorine and aluminum. Aluminum chloride has a low melting point and boiling point, and it will sublime, and it is an ionic covalent compound. Molten aluminum chloride is not easy to conduct electricity [1], unlike most salts containing halogen ions (such as sodium chloride).
AlCl3 adopts the "YCl3" structure, which is the most densely packed layered structure of Al3+ cubic. [2] In AlBr3, Al3+ occupies the gap between adjacent tetrahedrons of the Br− most densely packed frame. When melted, AlCl3 forms a volatile dimer Al2Cl6, which contains two three-center four-electron chlorine bridge bonds. At higher temperatures, the Al2Cl6 dimer dissociates to form a flat triangular AlCl3, which is similar in structure to BF3.
Aluminum chloride is a colorless transparent crystal or white and slightly yellowish crystalline powder. When aluminum chloride vapor is dissolved in a non-polar solvent or in a molten state, it exists in the form of covalent dimeric molecules. It is soluble in water and many organic solvents. The aqueous solution is acidic. In the presence of aromatic hydrocarbons, the mixture of aluminum chloride and aluminum can be used to synthesize bis(aromatic hydrocarbon) metal complexes. For example, diphenylchromium is prepared by Fischer-Hafner synthesis from specific metal halides. Low concentration of basic aluminum chloride is often one of the ingredients of antiperspirants, and patients with hyperhidrosis will have a higher concentration (12% or higher) when using it.
Physical and chemical properties: Appearance is white or light yellow granules or powder. Relative density 2.44 (25℃), melting point 190℃ (253KPa), incombustible, easily soluble in water, soluble in ethanol, chloroform, carbon tetrachloride, slightly soluble in benzene, strong water absorption, very deliquescent, exposed when exposed The air easily absorbs moisture and hydrolyzes into hydrogen chloride. It is highly corrosive and can form complexes with many inorganic and organic compounds. And the products are easy to decompose.
Uses: Used as a catalyst for organic synthesis, such as medicine, dyes, fragrances, liquid crystals, flame retardants, petroleum cracking, rubber synthesis, water treatment and other industries. Used in the manufacture of pesticides and organoaluminum compounds, also used in metal smelting, lubricating oil synthesis, food-grade products used as leavening agents, and pectin flocculants.