The INTERNET Database of Periodic Tables
There are hundreds of periodic tables in web space, but there is only one comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Dr Mark R Leach.
Janet's Helicoidal Classification
Janet's Helicoidal Classification, essentially his left-step formulation in its spiral version (ref. Charles Janet, La Classification Hélicoïdale des Éléments Chimiques. Beauvais: Imprimerie Départementale de l'Oise. 1928). Information supplied by Philip Stewart:
© Mark R. Leach 1999-
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counter started in 2011