Oxygen ionic compound with aluminum

Unprotected aluminum metal reacts with oxygen in air, forming the white coating you can observe on aluminum objects such as lawn furniture. Explain the formation of an ionic compound from the elements aluminum and oxygen. 

C02-0071. Aluminum is one of the few elements that forms cations with +3 charge. What are the chemical formulas of the ionic compounds that form between aluminum and (a) oxygen (b) fluorine ... 

Corrosion can also occur by a direct chemical reaction of a metal with its environment such as the formation of a volatile oxide or compounds, the dissolution of metals in fused metal halides. The reaction of molybdenum with oxygen and the reaction of iron or aluminum with chlorine are typical examples of metal/gas chemical reactions. In these reactions, the metal surface stays film-free and there is no transport of electrical charge.1 Fontana and Staehle2 have stated that corrosion should include the reaction of metals, glasses, ionic solids, polymeric solids and composites with environments that embrace liquid metals, gases, aqueous and other nonaqueous solutions. 

Metal and nonmetal form an ionic compound. A metal, such as aluminum, reacts with a nonmetal, such as oxygen. The change in O.N. s shows that the metal is oxidized, so it is the reducing agent the nonmetal is reduced, so it is the oxidizing agent. 

Because aluminum tends to form the cation (Al ) and oxygen the anion (0 ) in ionic compounds, the transfer of electrons is from A1 to O. There are three valence electrons in each A1 atom each O atom needs two electrons to form the ion, which is isoelectronic with neon. Thus, the simplest neutralizing ratio of aF to is 2 3 two Al ions have a total charge of +6, and three ions have a total charge of —6. 

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