Periodic Table
T-Shirts & more
from the

Merch Store

previous home next

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: 

  Text Search:       

The 10 Periodic Tables most recently added to the database:

2010   Epicylindrical Periodic Table
2018   Creating a Symbol of Science: The Development of a Standard Periodic Table of the Elements
1969   100 Years of the Periodic Law of Chemical Elements
2024   Cylindrical Periodic Table with Seven Vertical Columns
1976   Atomic & Ionic Radii Periodic Table
1944   Emerson's Spiral Formulation
2024   Marks' Aufspaltung Formulation
2024   Bilateral Symmetry in the Periodic Binodic Table
2008   Franklyn's Periodic Table
2024   Periodic Table of Food Initiative (PTFI)

Year:  2010 PT id = 1310

Epicylindrical Periodic Table

An Epicylindrical Periodic Table by Steven Fowkes, who writes: "All the twist is confined to the s orbitals, 1/2 slant x 2 elements = one period lower."  

Published in the Reed College Alumni Magazine March 2010.

Top of Page

Year:  2018 PT id = 1309

Creating a Symbol of Science: The Development of a Standard Periodic Table of the Elements

Robinson, Ann E., "Creating a Symbol of Science: The Development of a Standard Periodic Table of the Elements" (2018). Doctoral Dissertations. 1385. Download and view the PDF.

See Ann E. Robinson's ORCID page.

Mark Leach writes:

"An excellent, comprehensive study that is full of details and references."

Top of Page

Year:  1969 PT id = 1308

100 Years of the Periodic Law of Chemical Elements

A Soviet Union publication in Russian celebrating Medeleeve's seminal work of 1869: 100 Years of the Periodic Law of Chemical Elements, X Centennial (Jubilee) Mendeleev Congress. The work is the product of 23 Authors. (Thanks to Ann E. Robinson, René Vernon & Valery Tsimmerman for the info.)

Top of Page

Year:  2024 PT id = 1307

Cylindrical Periodic Table with Seven Vertical Columns

The Cylindrical Periodic Table with Seven Vertical Columns by Laith H. M. Al-ossmi, College of Engineering, University of Thi-Qar, Iraq; Thi-Qar University Pres. Read the full paper here.

Abstract: In this article, a new model of the periodic table in cylindrical form wrapped around its outer circumference is presented, departing from the traditional periodic table of elements adopted by the International Union of Pure and Applied Chemistry (IUPAC). The cylinder is designed to encompass seven periodic periods, with elements distributed throughout based on their atomic order. This design allows for six vertical columns on the surface of the cylinder to represent the distribution of elements.

Top of Page

Year:  1976 PT id = 1306

Atomic & Ionic Radii Periodic Table

A periodic table showing atomic and ionic radii from Chem Libre Texts. The text says: Figure 3.7. Source: Ionic radius data from R. D. Shannon, "Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides," Acta Crystallographica 32, no. 5 (1976): 751–767.

Mark Leach writes:

"I came across this periodic table while researching an exam question with a student: Which ion is larger: Na+ or F?

"Note that N3–, O2–, F, Ne, Na+, Mg2+ & Al3+ are all isoelectronic in that they all have the same electronic configeration: 1s2, 2s2, 2p6. The only property that changes is the nuclear charge, which increases from + 7 to + 11.

"Thus, N3– will be the largest and Al3+ the smallest in this set of isoelectronic species as the increasing nuclear charge pulls the electrons closer. Likewise from P3– to Sc3+ which are all 1s2, 2s2, 2p6, 3s2, 3p6."

Top of Page

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?)

Other features:

Top of Page

Year:  2024 PT id = 1304

Marks' Aufspaltung Formulation

John Marks' Aufspaltung (or "Splitting") formulation, after Mendeleyev (1869), Ramsay (1915) & Sommerfeld (1916).

Top of Page

Year:  2024 PT id = 1303

Bilateral Symmetry in the Periodic Binodic Table

René Vernon, who developed these ideas, writes:

This table is adapted from the work of Gutiérrez-Samanez (2020), who discusses mathematising the chemical periodic system as a grid, which leads to a quadratic function or “binódica function” formed by pairs of periods or binodos (dyads).

The difference is that whereas Gutiérrez-Samanez showed the first pair of periods as H-He and Li-Be, this table shows the first period as e-n and H-He. Here, e is the electron and n is the neutron. Each pair of periods is shown pancake style rather than in a single row. The formula for the length of each paired period or binode is 2n2 = 2, 8, 16, 32.

The idea of paired periods has a long history; it seems to have originated with Werner in 1905.

According to Jensen:

"The temptation to read more into the shape of the table than is really there is almost overwhelming. Even someone as great as Werner was tempted (1905). Having postulated a missing element between H and He, he decided to perfect the symmetry of his table by guaranteeing that rows of differing length always occurred in pairs. Consequently, he further postulated a row of three missing elements lying above the H-X-He row."

Rydberg (1913, pp. 12–13) used a formula 4n^2 for the number of elements in the paired periods: 4, 16, 32, 64. This formula is also used by Gutiérrez-Samanez.

Paired periods were also used by Janet (1928), Saz (1931), Achimov (1946) and Baca Mendoza (1953).


Top of Page

Year:  2008 PT id = 1302

Franklyn's Periodic Table

Franklyn writes on Electronic Orbital Periodicity Mendelevian grouping is only one possible organizational scheme, regardless of the schematic choice. A table is useful only to the extent that it provides easy reference to data and comparison. Most everyone who has considered arranging elements in tabular form has pondered what layout best serves the purpose. Below is a table I once made to determine the electronic shell and orbital structure of any element at a glance. Everything to the left and above the elements position indicates the complete full orbitals for those shells. Actually you can see the goup memebers run diagonally from upper left to lower right This arrangement shows that the progression of successive electrons is not straight forward with regard to placement within the atoms. The Mendelevian sequence begining with period 6 through the Lanthanides back to period 6 transition metals until Radon, continuing with period 7 ending with the first member of the Actinides, is as follows:

Thanks to René Vernon for the tip!

Top of Page

Year:  2024 PT id = 1301

Periodic Table of Food Initiative (PTFI)

Imagine a world where farmers choose to grow specific foods to combat food insecurity and diet-related chronic diseases using practices that are also good for the planet. A world where people everywhere are enabled to select customized diets that support their vitality. This future harnesses the power of food not only as a solution to hunger, but as an essential resource to support the well-being of communities and the environment.

The Periodic Table of Food Initiative (PTFI) is accelerating this future to empower data-driven solutions to our most pressing food system challenges: climate change, biodiversity loss, and malnutrition.

Visit the website:

Top of Page

previous home next
What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

Queries, Suggestions, Bugs, Errors, Typos...

If you have any:

Suggestions for links
Bug, typo or grammatical error reports about this page,

please contact Mark R. Leach, the author, using

This free, open access web book is an ongoing project and your input is appreciated.