Today, there is a matter related to the formula of aluminum-fluoride ions. For aluminum, metals are also active; for fluoride, halogen elements are also active. The combination of the two forms the formula of this ion.

Aluminum often shows positive trivalent, because its outer electrons are easy to lose. Fluorine is always negative monovalent, because it seeks to cut the electron. According to the principle of charge balance, in order to form a stable compound, an aluminum ion needs to be combined with trifluoride ions to achieve charge neutralization.

Therefore, the formula of aluminum-fluoride ion is\ (AlF_ {3}\). This formula also shows the ratio of aluminum to fluoride, and also shows the balance of its charge. In the field of chemistry, this formula is the basis of knowledge, and scholars cannot ignore it.