What is the formula for sodium diaquatetrachloroaluminate(III)?

To understand why the formula for sodium diaquatetrachloroaluminate(III) is represented as Na3[Al(H2O)2Cl4], let's break down the components of this chemical name.

The prefix "diaqua" indicates the presence of two water molecules (H2O) coordinated to the aluminum ion (Al). The term "tetrachloro" signifies that there are four chloride ions (Cl) associated with the aluminum as well. The "(III)" denotes that aluminum is in the +3 oxidation state, which is typical for aluminum compounds.

In the formula Na3[Al(H2O)2Cl4]:

• The "Na3" part suggests that there are three sodium ions balancing the charge of the complex.

• The brackets encapsulate the anionic part of the compound, where Al is complexed with two water molecules and four chloride ions.

• The overall formula reflects that for every three sodium ions, there is one aluminum central atom coordinating with two water molecules and four chloride ions.

This correct representation allows for the proper stoichiometry and charge balance for a compound containing aluminum in a +3 oxidation state, making it a stable and viable structure in solution.