User:Spongeboop/Carbonyl group

Structure and reactivity
For organic compounds, the length of the C-O bond has limited changes from 120 picometers, which is standard for these bonds. Inorganic carbonyls have shorter C-O distances: CO, 113; CO2, 116; and COCl2, 116 pm.

The carbonyl carbon is typically electrophilic. A qualitative order of electrophilicity is RCHO (aldehydes) > R2CO (ketones) > RCO2R' (esters) > RCONH2 (amides).

Interactions between carbonyl groups and other substituents were found in a study of a protein called collagen. Substituents can affect carbonyl groups by addition or subtraction of electron density by means of a sigma bond. ΔHσ values are much higher when the substituents on the carbonyl group are more electronegative than carbon.

The polarity of C=O bond also enhances the acidity of any adjacent C-H bonds. Due to the positive charge on carbon and the negative charge on oxygen, carbonyl groups are subject to additions and/or nucleophilic attacks. A variety of nucleophiles attack, breaking the carbon-oxygen double bond, and leading to addition-elimination reactions. Nucleophiliic reactivity is often proportional to the basicity of the nucleophile and as nucleophilicity increases, the stability within a carbonyl compound decreases.

The pKa values of acetaldehyde and acetone are 16.7 and 19 respectively,

A special group of carbonyl compounds are dicarbonyl compounds, which can exhibit special properties.

Carbonyl compounds are most often created starting with an alcohol, primary alcohols generating aldehydes, and secondary alcohols creating ketones.[2]