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The INTERNET Database of Periodic Tables

There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D.

Use the drop menus below to search & select from the more than 1300 Period Tables in the database: 

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Year:  2022 PT id = 1277

Ramsay-Sommerfeld Periodic Table

John Marks has updated Scerri's 2006 Triad formulation. Marks writes:

"[This is] an expansion of Scerri´s 2006 triad formulation, but brings the lanthanides & actinides in from the cold. It is lso modelled on the way IUPAC constructed its 18-group PT (but with traditional group numbering), that is to say, the total of 22 groups is simply IUPAC's 18 plus the four extra f-groups. I am not sure if this counts as a "medium" or a "long" form.

"If this PT needs a name, it would be the Ramsay-Sommerfeld PT. It has Ramsay´s 1915 arrangement for H (copied by Eric Scerri in 2006) and Sommerfeld's "greater" and "lesser" periods (1916) in green and yellow respectively. It solves the 'exile' of the f-blocks without making it too unwieldy (22 instead of 32 groups). The yellow (transition series) are Sommerfeld's 'A' subgroups and the green (rare earth series) are Sommerfeld's 'B' subgroups."

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