Understanding and Naming Chemical Oxides
Classified in Chemistry
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Understanding Chemical Oxides
Binary combinations between oxygen and all other chemical elements except the noble gases and fluorine.
Formulating Oxides
Oxides have the following general formula: X2On, where:
- X is the symbol of the other element.
- 2 corresponds to the valence of oxygen.
- O is the symbol for oxygen.
- n is the valence of the other element (metal or nonmetal).
Naming Oxides: Three Classifications
Oxides are named using three classifications: Traditional, Systematic, and Stock.
Traditional Nomenclature for Oxides
Basic Oxides: These result from the combination of oxygen and a metal.
- If the metal has a single valence, the oxide is named "Oxide" followed by the name of the metal.
Examples:
- CaO: Calcium Oxide
- Na2O: Sodium Oxide
- If the metal has two valences, use suffixes to indicate the valence:
- -ous for the lower valence
- -ic for the higher valence
Examples:
- FeO: Ferrous Oxide (iron valence is 2)
- Fe2O3: Ferric Oxide (iron valence is 3)
Acidic Oxides
Acidic oxides result from the combination of oxygen and a nonmetal.
- If the nonmetal has a single valence, the oxide is named "Oxide" followed by the name of the nonmetal with the suffix -ic.
Example:
- B2O3: Boric Oxide
- If the nonmetal has two or more valences, use the following prefixes and suffixes:
| Valence | Elements (S, Se, Te) | Elements (N, P, As, Sb) | Elements (Cl, Br, I) |
|---|---|---|---|
| 2 | Hypo- -ous | Hypo- -ous | Hypo- -ous |
| 3 | -ous | -ous | |
| 4 | -ous | ||
| 5 | -ic | -ic | |
| 6 | -ic | ||
| 7 | Per- -ic |
Example:
- Br2O5: Bromic Oxide
Systematic Nomenclature for Oxides
For both acidic and basic oxides, use prefixes to indicate the number of atoms of each element in the molecule.
- mono- (1)
- di- (2)
- tri- (3)
- tetra- (4)
- penta- (5)
- hexa- (6)
- hepta- (7)
- octa- (8)
Apply the nomenclature to the simplified formula. The prefix mono- can be omitted, implying a single atom of that element.
Example:
- As2S3: Diarsenic Trisulfide
Stock Nomenclature for Oxides
For both acidic and basic oxides, use the word "Oxide" followed by the name of the element and its valence in Roman numerals within parentheses. Use the original, unsimplified formula to determine the valence. If an element has only one valence, parentheses are not needed.
Example:
- Fe2O3: Iron Oxide (III)