What is the formula for carbon monoxide?
The molecular formula for carbon monoxide is ##CO##.
Carbon monoxide is a . According to the rules used for naming , you need to use Greek prefixes to describe exactly how many atoms each element contributes to the formula.
The only catch here is to remember that the mono prefix is never used for the first element, but it is always used for the second one!
In your case, the fact that you have no prefix before carbon tells you that the compound only contains 1 carbon atom.
Likewise, the mono prefix present before the second element tells you that your compound only contains 1 oxygen atom.
Therefore, the chemical formula for carbon monoxide is ##CO##.