Naming Ionic Compounds

Fundamentals of Ionic Compounds

  • Ionic compounds are solids composed of positive ions (cations) and negative ions (anions) held by electrostatic attraction.
  • Formulas list the cation followed by the anion.
  • Compounds are electrically neutral; the sum of positive and negative charges in a formula unit must equal zero.

Naming Binary Ionic Compounds

  • Binary compounds contains ions from only two different elements: a metal and a nonmetal.
  • Rule: Name the metal cation followed by the nonmetal anion with the suffix modified to "-ide".
  • Examples:   - NaClNaCl: sodium chloride   - CaCl2CaCl_2: calcium chloride   - CsBrCsBr: cesium bromide

Transition Metals and Variable Charges

  • Transition metals and certain other elements can form ions with multiple possible charges (e.g., Fe2+Fe^{2+} and Fe3+Fe^{3+}).
  • A Roman numeral in parentheses must follow the cation name to indicate its specific charge.
  • The charge of the metal is calculated based on the known charge of the anion to ensure a neutral formula unit.
  • Examples:   - FeBr3FeBr_3: iron (III) bromide (Three Br−Br^- at −1-1 each requires an Fe3+Fe^{3+} ion).   - TiCl4TiCl_4: titanium (IV) chloride (Four Cl−Cl^- at −1-1 each requires a Ti4+Ti^{4+} ion).

Questions & Discussion

  • Prompt: "you try n a two o"
  • Response: Sodium is the cation and oxide is the anion; the name is sodium oxide (Na2ONa_2O).
  • Prompt: "You try. Six, MnF two"
  • Response: The compound contains two fluoride ions (F−F^-), each with a −1-1 charge. To maintain electrical neutrality, the manganese ion must have a charge of +2+2. The name is manganese (II) fluoride (MnF2MnF_2).