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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.

2019 has been designated the International Year of the Periodic Table as it is the 150th Anniversary of the formulation of Mendeleev's Tabelle I

 pre 1900 formulations  1900 to 1949 formulations  1950 to 1999 formulations  2000 to 2009 formulations    Spiral formulations  3 dimensional formulations
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1927

Le Roy's Periodic Table

R.H. LeRoy, Teaching the Periodic Classification of Elements, School Science and Mathematics 1927, 27: 793-799. This formulation thulium in group IC and has the actinides in the C groups, analogous to the lanthanides, two decades before Seaborg.

Rene adds:

"This 1927 formulation has several remarkable features. The actinides are shown in C groups, analogous to the lanthanides. {Ce, Th} and {Pr, Pa} are in groups C4, and C5, corresponding to their maximum oxidation states. The author shows {Nd, U} in group C6, which doesn't quite work since there is no Nd(VI).

"At the other end of the C groups, the author has Tm, Yb, and Lu as C3, C2, and CI, which doesn't quite work since there is no Lu(I). Nor would it work for Lr, as there is no Lr(I) as far as we know.

"Having said that, Le Roy's speculation as the existence of a transitional set of Ln/An does work (sort of) for the actinides. B-Al-Y-La-Ac are shown as main group metals; that would be consistent with their chemistry. The author refers to the noble gases as 'transitional'. The noble gases bridge the most reactive groups of elements in the periodic table – the alkali metals in group I and the halogens in group VII. That's a concept that's rarely referred to these days even though it's still quite valid.

"{Ga, In, Tl} are shown as B3 metals, falling just after {Zn,Cd, Hg} in group B2, and {Cu, Ag, Au} in group B1. That doesn't work for Ga etc.

"H is shown floating above the A elements, and in the transitional zone, with links to F and to Li.":

Thanks to John Marks for the tip, and to Rene for the comments/analysis!

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