ORGANIC and INORGANIC
There are quite a number of common definitions, but most of them are too restrictive and have exceptions. Incidentally there's a very good answer on the Web, to the question of "what is organic chemistry?"
* Organic compounds are produced by living things. Inorganic compounds are produced by non-living natural processes or by human intervention in the laboratory.
This was the most common definition of "organic" until Wohler's 1828 synthesis of urea (an organic compound) from ammonium cyanate (a salt, and ¿therefore? inorganic). But we no longer use this definition, for the simple reason that many compounds that everyone agrees are organic -- including "natural ...view middle of the document...
Furthermore there are now a number of indubitably organic compounds that are nevertheless stable salts. For more, see this answer.
* Organic compounds contain carbon. Inorganic compounds don't.
This definition is often given but is no help at all. What do we make of carbon dioxide, sodium cyanide, baking soda (sodium bicarbonate), ...?
* Organic compounds contain carbon-hydrogen bonds. Inorganic compounds don't.
sodium acetate |
* This is a much better definition, allowing us to call sodium acetylide "organic" but calcium carbide "inorganic," but it doesn't always work. We can certainly distinguish the compounds listed above as inorganic by this rule, but what about tetracyanoethylene, which is indubitably organic but contains no hydrogen atoms at all?
* Nevertheless, almost all "organic carbon" has carbon-hydrogen bonds, while all "inorganic carbon" does not have carbon-hydrogen bonds. Even if you call e.g. sodium acetate inorganic, everyone will agree that the carbon atom which is attached to the hydrogens is "organic carbon."
* Inorganic compounds contain metal atoms. Organic compounds don't.
This doesn't really work any too well either. Even leaving the huge field of organ metallic chemistry out of the running, are we really going to call soap (sodium salts of fatty acids) or the lipid bilayers forming cell membranes (again, salts of long-chain organic acids) "inorganic"???
* An organic compound is whatever an organic chemist...