Periodic Table |
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| What is the Periodic Table Showing? | Periodicity |
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. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).
| Year: 2005 | PT id = 28, Type = formulation |
Laing's Revised Periodic Table with the Lanthanides Repositioned
Michael Laing's "Revised Periodic Table with the Lanthanides Repositioned", from Foundations of Chemistry 7:203-233.
- The new system emphasizes oxidation states.
- The elements Eu and Yb fall directly below Ba, indicating the common oxidation state of 2+.
- Elements La, Gd, Lu fall in a column below Y, all having the dominant oxidation state 3+.
- Ce and Tb fall between Zr and Hf in keeping with their 4+ oxidation state. Pm (Z=61) lies immediately below Tc (Z=43), both without stable naturally occurring isotopes.
- The easily attained oxidation states of 2+ for Am and No, and 4+ for Bk are evident from the analogous positioning of the actinides.

Philip Stewart's modification of the Laing formulation:

Philip Stewart says (in a personal communication):
"It seems wrong to suggest an analogy between Pr to Sm and Dy to Tm with the V, Cr, Mn, Fe groups. I have pushed them to the right to suggest that those lanthanides are like the old group VIII (including the coinage metals); like them they cannot use all their outer electrons in bonding (with the exception of Ru viii and Os viii. I have treated the actinides differently to take account of Pa v and U vi. It's ability to lose the juxtaposition of Tc and Pm, but it is physical rather than chemical anyway."
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| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
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