Examples of aluminum in the following topics:
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- 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:
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- 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.
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- 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.
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- Aluminosilicate minerals are composed of aluminum, silicon, oxygen, and countercations.
- Sodium aluminosilicates are acidic salts that is composed of sodium, aluminum, silicon and oxygen.
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- 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:
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- Aluminum foil and copper wire are examples of metallic bonding in action .
- A sheet of aluminum foil is made up of metallic bonds.
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- 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.
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- Note that Lithium Aluminum Hydride (LiAlH4) is the strongest reducing agent listed, and it reduces all the substrates.
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- Ziegler-Natta catalysts are prepared by reacting certain transition metal halides with organometallic reagents such as alkyl aluminum, lithium and zinc reagents.
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- Two practical sources of hydride-like reactivity are the complex metal hydrides lithium aluminum hydride (LiAlH4) and sodium borohydride (NaBH4).
- These are both white (or near white) solids, which are prepared from lithium or sodium hydrides by reaction with aluminum or boron halides and esters.
- Lithium aluminum hydride is by far the most reactive of the two compounds, reacting violently with water, alcohols and other acidic groups with the evolution of hydrogen gas.
- The lithium, sodium, boron and aluminum end up as soluble inorganic salts.
- The acid catalyzed hydrolysis of the aluminum salts also effects the removal of the acetal.