Organic and Inorganic

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 products" which are routinely made by living things -- have been synthesized by humans. Some of these natural products are synthesized by the ton. And unquestionably organic molecules, such as the amino acid glycine, have been found in interstellar space where there are no living things.
Some people apparently still think this definition should hold, but it's just not so.
  * Inorganic compounds can form salts. Organic compounds can't.
This definition seems to work as a practical matter under very limited circumstances. For example, it allows us to distinguish between the organic and inorganic cyano group, which have rather different chemical behaviors in e.g. acetonitrile and sodium cyanide.
But this definition is far too limited. Not only are there plenty of inorganic compounds that don't form salts (for example, sulfur hexafluoride SF6), but there are a number of organic compounds that do form salts: not only carboxylic acids but amines, alcohols, and even acetylene can form salts. And how do we distinguish between (organic) sodium acetylide, NaCCH, and (inorganic) calcium carbide, CaCC?
Some chemists would call lithium acetylide, potassium acetate and sodium methoxide ("sodium methylate") inorganic, while calling acetylene, acetic acid and methanol (from which...