Natura - nature
Status: extant
   actualia - actual entities
  Status: extant
     Mundus Plinius - physical world
    Status: extant
       naturalia - natural bodies
      Status: extant
         "crystal-kingdom"
        Status: extant
           chemical substances
          Status: extant
             chemical compounds
            Status: extant
               Class azines [R2C=NN=CR2]
              Status: extant
                 Class ketazines [R2C=NN=CR2]
                Status: extant