Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class carboxylic acids - RC(=O)OH
                 01.1 acetic acid - CH₃C(=O)OH
                 01.2 acetic acid derivatives
                 02 acrylic acid
                 03 adipic acid
                 04 benzoic acid
                 05 butyric acid
                 06 carbamic acid
                 07 formic acid
                 08 glutaric acid
                 09 malonic acid
                 10 methacrylic acid
                 11 oxalic acid
                 12 oxamic acid
                 13.1 phthalic acid
                 13.2 isophthalic acid
                 13.3 terephthalic acid
                 14.1.1.1 propionic acid
                 14.1.1.2 propionic acid derivatives - CR₃CR₂C(=O)OH
                 14.1.2 3-chloropropanoic acid
                 14.2.1 lactic acid
                 14.2.2 3-chloro-2-hydroxypropanoic acid
                 15 succinic acid
                 4.1.1 Class fatty acids