Silver chloride formula
The silver chloride formula is AgCl. The compound is electrically neutral and contains one silver ion and one chloride ion per formula unit.
Ions and charge balance
Silver commonly forms the cation \(\mathrm{Ag^+}\) in simple ionic compounds, and chlorine forms the anion \(\mathrm{Cl^-}\). Charge neutrality requires the total positive charge to equal the total negative charge.
| Species | Ion formed | Charge | Role in AgCl |
|---|---|---|---|
| Silver | \(\mathrm{Ag^+}\) | \(+1\) | One cation per formula unit |
| Chloride | \(\mathrm{Cl^-}\) | \(-1\) | One anion per formula unit |
A 1:1 ratio balances the charges:
\[ (+1) + (-1) = 0 \]The resulting neutral formula unit is AgCl.
Naming and oxidation state
AgCl is named silver(I) chloride. The Roman numeral (I) indicates the oxidation state \(+1\) for silver in this compound. In many introductory contexts, “silver chloride” is understood as AgCl because \(\mathrm{Ag^+}\) is the common simple silver cation in aqueous chemistry.
Aqueous chemistry context
Silver chloride is a classic precipitation product when \(\mathrm{Ag^+}\) meets \(\mathrm{Cl^-}\) in water. A representative molecular equation is
\[ \mathrm{AgNO_3(aq) + NaCl(aq) \rightarrow AgCl(s) + NaNO_3(aq)}. \]The corresponding net ionic equation highlights the substance-forming event:
\[ \mathrm{Ag^+(aq) + Cl^-(aq) \rightarrow AgCl(s)}. \]Common pitfalls
Charge mismatch errors are common when writing ionic formulas. AgCl is not \(\mathrm{AgCl_2}\) or \(\mathrm{Ag_2Cl}\) because \(\mathrm{Ag^+}\) and \(\mathrm{Cl^-}\) already balance at a 1:1 ratio. Confusion between “chlorine” and “chloride” also appears frequently; chloride denotes the anion \(\mathrm{Cl^-}\), not neutral \(\mathrm{Cl_2}\).