Question 3.6: Binary Ionic Compounds Give each binary ionic compound a sys...
Binary Ionic Compounds
Give each binary ionic compound a systematic name and a common name.
(a) CuO (b) \text{Cu}_{2}\text{O}
Strategy
The name of a binary ionic compound consists of two words. First is the name of the cation followed by the name of the anion. Because transition metals typically form more than one cation, the charge on the cation must be indicated by a Roman numeral in parentheses following the name of the transition metal or by using the suffix –ic to show the higher of the two possible cation charges or the suffix –ous to show the lower of the two possible cation charges.
| Analysis | Ions Present | Chemical Compound |
| One \text{Cu}^{2+} ion must combine with one \text{O}^{2-} ion to balance the charges. | \text{Cu}^{2+} and \text{O}^{2-} | CuO |
| Two \text{Cu}^{+} ions must combine with one \text{O}^{2-} ion to balance the charges. | \text{Cu}^{+} and \text{O}^{2-} | \text{Cu}_{2}\text{O} |
(a) Systematic name: copper(II) oxide. Common name: cupric oxide.
(b) Systematic name: copper(I) oxide. Common name: cuprous oxide.
Remember in answering part (b) that we ignore subscripts in naming binary ionic compounds. Therefore, the 2 in \text{Cu}_{2}\text{O} is not indicated in the name. You know that two copper(I) ions are present because two positive charges are needed to balance the two negative charges on an \text{O}^{2-} ion.
■ Quick Check 3.6
Give each binary compound a systematic name and a common name.
(a) FeO (b) \text{Fe}_{2}\text{O}_{3}