Aluminium Oxide Valency

The valency of an element or atom is the number of outermost shell electrons that it has available to form covalent, ionic or metallic bonds. The aluminium oxide valency is +3 and the oxygen valency is -2. Aluminium is an element belonging to the 13th periodic table group while oxygen belongs to the 16th. Therefore, the two atoms have different valency values, which can result in polar or non-polar compounds. In a polar compound, the difference in the electronegativity of the two bonding atoms results in the formation of a negative and positive pole respectively.

The aluminum atoms in aluminium oxide have a total of 24 valence electrons, which are used to form 2 single covalent and 2 double bonds. The remaining 12 electrons are unshared and are known as lone pair electrons. Each of the aluminium atoms have two lone pair electrons, while each of the oxygen atoms has three lone pair electrons.

Al2O3 has a trigonal planar structure with a sp2 hybridization. The bond angle within the aluminium-oxygen molecule is 120 degrees.

Aluminium oxide is a solid ionic compound that is insoluble in water. Its chemistry is interesting, as it can act as either an acid or base. Upon reaction with an acid, it acts as an acid to produce the salt aluminium chloride (AlCl3) while when reacted with a base such as NaOH, it acts as a base. This makes it an amphoteric compound that has the characteristics of both metals and non-metals.