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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 1944:

1944   Müller's Tree System
1944   Discovery of Americium
1944   Discovery of Curium
1944   Emerson's Long Chart Modified to Show Atomic Structure
1944   Emerson's Spiral Formulation

Year:  1944 PT id = 293

Müller's Tree System

In 1944 Müller produced a formulation based on Darwin's tree of life (from van Spronsen):

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Year:  1944 PT id = 875

Discovery of Americium


Americium, atomic number 95, has a mass of 243 au.

Synthetic radioactive element. It is used in smoke detectors, and so – surprisingly – is present most houses and buildings.

Americium was first observed in 1944 by G. T. Seaborg, R. A. James, O. Morgan and A. Ghiorso.

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Year:  1944 PT id = 876

Discovery of Curium


Curium, atomic number 96, has a mass of 247 au.

Synthetic radioactive element.

Curium was first observed in 1944 by G. T. Seaborg, R. A. James and A. Ghiorso.

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Year:  1944 PT id = 1238

Emerson's Long Chart Modified to Show Atomic Structure

Edgar I. Emerson 1944, A chart based on atomic numbers showing the electronic structure of the elements, J. Chem. Educ. 1944, 21, 5, 254.

A WWII chart showing neutronium over He, and a split d-block.

Thanks to René for the tip!

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Year:  1944 PT id = 1305

Emerson's Spiral Formulation

Emerson EI, 1944, A new spiral form of the periodic tableJChemEd., vol. 21, no. 3, pp. 111–115

René Vernon writes:

Emerson says that the elements in the A groups are called the representative elements because, as Eble states, they "include metals, nonmetals, inert elements, liquids, and gases." Eble RL, 1938, Atomic structure and the periodic table, JChemEd., vol. 15, p. 575

Note the inclusion in Emerson’s table of the neutron as element 0. Astonishingly, Emerson writes: "Element 0, possibly neutron [sic], is considered as a noble gas. Because of its probable chemical inertness and extreme density it might not be detected in a sizeable amount until some future scientist succeeds in sampling the center of the Earth." (p. 111)

(Mark Leach adds: The date is 1944 when the Manhattan Project was in full swing and nothing was being published about nuclear physics and/or neutron interactions. This idea may have come from some type of Popular Science story?)

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What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

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