How do you name ionic compounds with roman numerals?

You name ionic compounds with Roman numerals according to the format: "name of metal(oxidation number in parentheses) name of anion".

All metals except Al, Zn, and those in Groups 1 and 2 can have more than one oxidation number.

When we name their compounds, we have to specify which oxidation number is involved.

The names consist of two words:

• name of metal(oxidation number in parentheses)
• name of anion

  Note: There is no space between the name of the metal and the opening parenthesis.

  We work backwards from the anion to determine the oxidation number of the metal.

  For example, manganese can form either MnO or MnO₂·

  The oxidation number of O is -2.

  So the oxidation number of Mn in MnO is +2, and the name of the compound is manganese(II) oxide.

  The oxidation number of Mn in MnO₂ is +4, and the name of the compound is manganese(IV) oxide.

  The most common ions with multiple oxidation numbers are shown below.

  Here's a video on naming and writing formulas for ionic compounds with Roman numerals.