The compound with the formula CO is called carbon monoxide. Suggest why it is not simply called ‘carbon oxide’.
The correct answer and explanation is:
The compound CO is not simply called carbon oxide because carbon can form more than one oxide, and a more specific naming system is needed to distinguish between them. The name carbon monoxide indicates that the molecule contains one oxygen atom (“mono” meaning one), whereas carbon dioxide (CO₂) contains two oxygen atoms. This naming follows the rules of the systematic nomenclature in chemistry, specifically the IUPAC naming system for covalent compounds, which uses Greek prefixes to show the number of atoms of each element.
Explanation (300 words):
Carbon forms multiple oxides, primarily carbon monoxide (CO) and carbon dioxide (CO₂). Both are compounds consisting of carbon and oxygen, but their chemical and physical properties are very different due to their differing compositions. If we simply used the name “carbon oxide,” it would be ambiguous, as it does not specify how many oxygen atoms are present in the compound. That would lead to confusion when distinguishing between CO and CO₂.
To avoid this, chemists follow the IUPAC (International Union of Pure and Applied Chemistry) naming system for binary covalent compounds—those made of two nonmetals. In this system, prefixes are used to indicate the number of atoms of each element in the molecule. For example:
- Carbon monoxide (CO): “mono” means one oxygen atom.
- Carbon dioxide (CO₂): “di” means two oxygen atoms.
The prefix “mono-” is usually omitted for the first element, which is why CO is called “carbon monoxide” rather than “monocarbon monoxide.”
This system is particularly important when an element can form more than one compound with another element, a situation known as variable oxidation states or multiple oxidation numbers. Carbon exhibits different oxidation states in CO and CO₂, so precise naming helps avoid misunderstanding and supports accurate chemical communication.
In summary, CO is called carbon monoxide instead of carbon oxide to distinguish it clearly from other oxides of carbon and to follow established rules that reflect the compound’s exact composition.