aluminum

(noun)

A metallic chemical element (symbol Al) with an atomic number of 13.

Related Terms

Examples of aluminum in the following topics:

  • Aluminum

    • Aluminum is a soft, silvery metal in the boron group of the periodic table.
    • The important aluminum hydride is lithium aluminum hydride (LiAlH4), which is used as a reducing agent in organic chemistry.
    • Aluminum is the most widely used non-ferrous metal.
    • For example, the common aluminum foils and beverage cans are alloys of 92% to 99% aluminum.
    • Some of the many uses for aluminum metal are in:

  • The Incomplete Octet

    • While most elements below atomic number 20 follow the octet rule, several exceptions exist, including compounds of boron and aluminum.
    • Boron and aluminum, from Group III (or 13), display different bonding behavior than previously discussed.
    • Compounds of aluminum follow similar trends.
    • Aluminum trichloride (AlCl3), aluminum hydride (AlH3), and aluminum hydroxide (Al(OH)3) indicate a valence of three for aluminum, with six valence electrons in the bonded molecule.
    • However, the stability of aluminum hydride ions (AlH4-) indicates that Al can also support an octet of valence shell electrons.

  • Basic and Amphoteric Hydroxides

    • One of the most common and familiar examples of an amphoteric hydroxide is aluminum hydroxide, Al(OH)3.
    • We will now consider aluminum hydroxide's reaction in a strongly basic solution:
    • Here, aluminum hydroxide picks up an hydroxide ion out of solution, thereby acting as a Lewis acid.
    • In addition to aluminum, metals such as zinc, tin, lead, and beryllium can also form amphoteric oxides or hydroxides.
    • Aluminum hydroxide can act as either a Bronsted-Lowry base, by accepting protons from an acidic solution, or as a Lewis acid, by accepting an electron pair from hydroxide ions in a basic solution.

  • Aluminosilicates

    • Aluminosilicate minerals are composed of aluminum, silicon, oxygen, and countercations.
    • Sodium aluminosilicates are acidic salts that is composed of sodium, aluminum, silicon and oxygen.

  • Reduction

    • Indeed, it was noted earlier that carboxylic acids themselves are reduced to alcohols by lithium aluminum hydride.
    • Furthermore, oxygen forms especially strong bonds to aluminum.
    • Lithium aluminum hydride reduces nitriles to 1ยบ-amines, as shown in the following equation.
    • The most fruitful approach to this end has been to attach alkoxy or alkyl groups on the aluminum.
    • The first (LtBAH) is a complex metal hydride, but the second is simply an alkyl derivative of aluminum hydride.

  • The Solubility of Amphoteric Metal Hydroxides

    • In general, these compounds tend to be more basic than acidic; thus, the oxides and hydroxides of aluminum, iron, and zinc all dissolve in mildly acidic solution:

  • Bonding in Metals: The Electron Sea Model

    • Aluminum foil and copper wire are examples of metallic bonding in action .
    • A sheet of aluminum foil is made up of metallic bonds.

  • Overview of Reducing Agents

    • Note that Lithium Aluminum Hydride (LiAlH4) is the strongest reducing agent listed, and it reduces all the substrates.

  • Ziegler-Natta Catalytic Polymerization

    • Ziegler-Natta catalysts are prepared by reacting certain transition metal halides with organometallic reagents such as alkyl aluminum, lithium and zinc reagents.

  • Pictures of Modes

    • This particular stadium consists of an aluminum plate 194 mm long by 100 mm wide by about 3 mm thick.