What term is used to describe the carbonyl group in organic compounds?

The carbonyl group in organic compounds is described by the formula -C=O. This functional group consists of a carbon atom double-bonded to an oxygen atom. It is a crucial component in many classes of organic compounds, including aldehydes, ketones, carboxylic acids, and esters. The carbonyl group is characterized by its distinct polarity, which influences the reactivity and properties of the compounds it is contained within.

As for the other options, while they represent other functional groups, they do not describe the carbonyl group. The second option, -R-O-R, denotes an ether group, where R represents alkyl or aryl groups connected by an oxygen atom. The third option, -R-NH-R', refers to an amine group, which consists of nitrogen bonded to one or more carbon-containing substituents. Lastly, the fourth option, -O2R, is not a standard representation of any typical functional group and does not relate to the carbonyl structure. Thus, -C=O is indeed the correct term for the carbonyl group in organic chemistry.