1. In this example, we’ll write the formula for another ionic compound with a multivalent metal.

2. We’re asked to write the formula for the compound lead(IV) sulphide. Pb 4+ S 2– +4–2 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide.

3. The metal lead is found here. It forms an ion with either a positive 2 charge, or a positive 4 charge. Write the formula for the compound lead(IV) sulphide.

4. And for sulphide we go to the element sulphur. The sulphide ion it forms has a charge of negative 2. Write the formula for the compound lead(IV) sulphide.

5. The roman numeral I V means that the lead ion with a positive 4 charge is used. Pb 4+ S 2– +4–2 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide.

6. So the metal ion in this compound is Pb 4 plus Pb 4+ S 2– +4–2 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide.

7. And the non-metal ion is the sulphide ion, S 2 minus Pb 4+ S 2– +4–2 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide.

8. With one lead IV ion and one sulphide ion, the charges do not add up to zero. Pb 4+ S 2– +4–2 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide. Total Positive Charge Total Negative Charge These DO NOT add up to zero

9. To make charges balance, we add another sulphide ion Pb 4+ S 2– +4–2 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide. Total Positive Charge

10. And now the total negative charge is negative 4 Pb 4+ S 2– +4–4 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide. Total Positive Charge Total Negative Charge

11. And now the charges are balanced, +4 and negative 4 add up to zero Pb 4+ S 2– +4–4 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide. Total Positive Charge Total Negative Charge NOW these add up to zero

12. We have one lead ion for every 2 sulphide ions, so the formula is Pb 4+ S 2– +4–4 S 2– Write the formula for the compound lead(IV) sulphide.

13. PbS 2 Pb 4+ S 2– +4–4 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide.

14. We’ve now answered the question. The formula for lead (IV) sulphide is PbS 2. Notice there are no charges or roman numerals in the final formula. Pb 4+ S 2– +4–4 PbS 2 S 2– Write the formula for the compound lead(IV) sulphide. Formula: