Modern definition

Organic chemistry is the chemistry of carbon compounds

• (hydrocarbons and their derivatives), with the exception of the carbon oxides (CO, CO₂), carbonates, bicarbonates and metal cyanides, which are studied with inorganic chemistry.
• Inorganic chemistry deals with all the other elements.

• One might guess that inorganic compounds are more numerous, since they involve all the other elements.
• The truth is the opposite: there are more than 10 million known organic compounds (and the number grows daily), whereas inorganic compounds do not exceed about half a million.
• The ratio is roughly 20 : 1.