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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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Periodic Tables from the year 1861:

1861   Discovery of Rubidium
1861   Discovery of Thallium

Year:  1861 PT id = 817

Discovery of Rubidium


Rubidium, atomic number 37, has a mass of 85.468 au.

Rubidium is a Group 1 element, and these are often referred to as the "alkali metals".

Rubidium was first observed, but not isolated in pure form, in 1861 by R. Bunsen and G. R. Kirchhoff.

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Year:  1861 PT id = 861

Discovery of Thallium


Thallium, atomic number 81, has a mass of 204.384 au.

Thallium was first observed or predicted in 1861 by W. Crookes and first isolated in 1862 by C.-A. Lamy.

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What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

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