# How can I write the formula for sodium chloride?

The formula for sodium chloride is NaCl. This represents a ratio of one sodium ion $N {a}^{+}$ , to one chloride ion $C {l}^{-}$. This is an ionic compound made up of positive and negative ions. The ions are held together by strong electrostatic forces called ionic bonds. Overall ionic compounds have no charge because the charges cancel each other out, so the charges on the ions are not shown in the formula.