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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 1100 Period Tables in the database:

Text search:       

The 8 Periodic Tables most recently added to the database:

2019   Green & Sustainable Chemistry, Periodic Table of
2020   16 Dividing Lines Within The Periodic Table
2020   Zig-Zag Line, Periodic Table
2020   Allahyari & Oganov: Mendeleev Numbers & Organising Chemical Space
2020   Shukarev's Periodic System (redrawn by Vernon)
1975   Shukarev's Periodic System
1947   Ageev's Crystalline Structures of The Elements
2020   Vernon's (Partially Disordered) 15 Column Periodic Table


Green & Sustainable Chemistry, Periodic Table of

The periodic table of the elements of green and sustainable chemistry by Paul T. Anastas & Julie B. Zimmerman, Green Chem., 2019,21, 6545-6566, (DOI: 10.1039/c9gc01293a). Also, there is a review article in Chemistry World.

Click image to enlarge:

Thanks to Eric Scerri for the tip! 
See the website and Eric's Twitter Feed.

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16 Dividing Lines Within The Periodic Table

René Vernon points out that there are 16 dividing lines within the periodic table.

A-Z Dividing Lines:

48-crash line: Named after the dramatic reduction in physical metallic character after group 11, Cd being Z = 48. Group 12 show few transition metal attributes and behave predominantly like post-transition metals.

Big bang line: H makes up about 73% of the visible universe.

Corrosive line: O, F, Cl = most corrosive nonmetals.

d-Block fault line: Group 3 show little d-block behaviour; group 4 is the first in which characteristic d-block behaviour occurs.

Deming line: Demarcates the metalloids from the pre-halogen nonmetals. The "reactive" nonmetals to the right of the metalloids each have a sub-metallic appearance (C, O, Se, I).

Edge of the world line: No guesses for this one.

Klemm line: Klemm, in 1929, was the first to note the double periodicity of the lanthanides (Ce to Lu). Lockyer line: After the discoverer of He, the first element not found on Earth.

Ørsted line: After the magnetic effects believed to be responsible for Mn having a crystalline structure analogous to white P; Tc: First radioactive metal; Re: Last of the refractory metals; "most radioactive" of the naturally occurring elements with stable isotopes. Fe: First of the ferromagnetic metals; Ru: First noble metal; Os: Densest of naturally occurring metals. The number of unpaired d electrons peaks in group 7 and reduces thereafter.

Platypus line: Tl shows similarities to Rb, Ag, Hg, Pb.

Poor metal line: Most metals (80%) have a packing factor (PF)3 68%. Ga: Has a crystalline structure analogous to that of iodine. BCN 1+6.* PF 39.1%. Melts in your hand. In: Partly distorted structure due to incompletely ionised atoms. BCN 4+8. PE 68.6%. Oxides in preferred +3 state are weakly amphoteric; forms anionic indates in strongly basic solutions. Tendency to form covalent compounds is one of the more important properties influencing its electro-chemical behaviour. Sn: Irregularly coordinated structure associated with incompletely ionised atoms. BCN 4+2. PF 53.5%. Oxides in preferred +2 state are amphoteric; forms stannites in strongly basic solutions. Grey Sn is electronically a zero band gap semimetal, although it behaves like a semiconductor. Diamond structure. BCN 4. PF 34.0%. Pb: Close-packed, but abnormally large inter-atomic distance due to partial ionisation of Pb atoms. BCN 12. PF 74%. Oxide in preferred +2 state is amphoteric; forms anionic plumbates in strongly basic solutions. Bi: Electronic structure of a semimetal. Open-packed structure (3+3) with bonding intermediate between metallic and covalent. PF 44.6%. Trioxide is predominantly basic but will act as a weak acid in warm, very concentrated KOH. Can be fused with KOH in air, resulting in a brown mass of potassium bismuthate.

Seaborg line: No f electrons in gas phase La, Ac and Th atoms.

Triple line: N = gas; S = solid; Br = liquid.

Zigzag lobby: H needs no intro. Li: Many salts have a high degree of covalency. Small size frequently confers special properties on its compounds and for this reason is sometimes termed 'anomalous'. E.g. miscible with Na only above 380° immiscible with molten K, Rb, Cs, whereas all other pairs of AM are miscible with each other in all proportions. Be: Has a covalent component to its otherwise predominately metallic structure = low ductility. Lowest known Poisson's ratio of elemental metals. Amphoteric; predominately covalent chemistry atypical of group 2. Some aspects of its chemical properties are more like those of a metalloid.

Zigzag line: Eponymous metal-nonmetal dividing line.

Zintl line: Hypothetical boundary highlighting tendency for group 13 metals to form phases with a various stoichiometries, in contrast to group 14+ that tend to form salts with polymeric anions.

* BCN = bulk coordination number

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Zig-Zag Line, Periodic Table

Periodic Table showing the (regular) zig-zag line by René Vernon who writes:

"It is curious that the full extent of the line has never been properly mapped (to my knowledge).

"Elements on the downside of the line generally display increasing metallic behaviour; elements on the topside generally display increasing nonmetallic behaviour.

"When you see the line you will usually see only about a quarter of it. The line actually runs all the way across the periodic table, as shown, for a total of 44 element box sides.

"Interpretations vary as to where the line runs. None of these is better than any other of them, provided the interpretation is explained to you. The thick black line (at least in the p-block) is the most common version. The metalloids tend to lie to either side of it.

"Polonium and astatine are shown here as post-transition metals although either or both of them are sometimes shown as metalloids (or, in the case of astatine, as a halogen). Polonium conducts electricity like a metal and forms a cation in aqueous solution. In 2013, astatine was predicted to be a centred cubic-metal Condensed Astatine: Monatomic and Metallic This prediction has been cited 35 times, with no dissenters. Astatine also forms a cation in aqueous solution. Oganesson is shown as having (as yet) unknown properties.

"The dashed lines show some alternative paths for the zigzag line.

"The lower one treats the metalloids as nonmetals since metalloid chemistry is predominately nonmetallic. The lower line and the upper line are sometimes shown together used when the metalloids are treated as neither metals nor nonmetals."

And in Janet Left-Step form:

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Allahyari & Oganov: Mendeleev Numbers & Organising Chemical Space

This formulation may not look like a periodic table, but look again.

Zahed Allahyari & Artem R. Oganov, Nonempirical Definition of the Mendeleev Numbers: Organizing the Chemical Space, J. Phys. Chem. C 2020, 124, 43, 23867–23878, A preprint version of the paper is available on the arxiv preprint server.


Organizing a chemical space so that elements with similar properties would take neighboring places in a sequence can help to predict new materials. In this paper, we propose a universal method of generating such a one-dimensional sequence of elements, i.e. at arbitrary pressure, which could be used to create a well-structured chemical space of materials and facilitate the prediction of new materials.

This work clarifies the physical meaning of Mendeleev numbers, which was earlier tabulated by Pettifor. We compare our proposed sequence of elements with alternative sequences formed by different Mendeleev numbers using the data for hardness, magnetization, enthalpy of formation, and atomization energy. For an unbiased evaluation of the MNs, we compare clustering rates obtained with each system of MNs.

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Shukarev's Periodic System (redrawn by Vernon)

Shukarev SA 1975, "On the image of the periodic system with the use of fifth move of late a-elements", Collection of Scientific and Methodological Articles on Chemistry. M.: Higher School, no 4, pp 3-12 (in Russian). Redrawn and commented upon by René Vernon:

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Shukarev's Periodic System

Shukarev SA 1975, "On the image of the periodic system with the use of fifth move of late a-elements", Collection of Scientific and Methodological Articles on Chemistry. M.: Higher School, no 4, pp 3-12 (in Russian).

The image has been re-drawn and commented upon.

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Ageev's Crystalline Structures of The Elements

Ageev NV 1947, The nature of the chemical bond in metal alloys (Izdvo Akad. Nauk SSSR, Moscow/Leningrad, p. 10

René Vernon writes:

"In this curious 18-column table, showing the crystalline structures of the elements, Ageev locates the predominately non-metallic groups on the left and the remaining groups on the right.

"It's odd that he located boron and aluminium on the far left over gallium, rather than over scandium. I suppose he did this so that gallium, indium, and thallium would not be mistaken for d-block metals.

"Reading from left to right then, Ageev's table could be said to be made up of five blocs:"

[1] the nonmetallic bloc
[2] the alkaline bloc
[3] the inner transition bloc
[4] the transition metal block
[5] a post-transition metallic bloc

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Vernon's (Partially Disordered) 15 Column Periodic Table

A formulation by René Vernon, who writes:

"Here is a 15-column table which is a hybrid of a Mendeleev 8-column table and an 18-column standard table. The key relocations are the p-block nonmetals to the far left; and the coinage and post-transition metals under their s and early d-block counterparts.

"Taking a leaf out of Mendeleev's playbook, I ignored atomic number order when this seemed appropriate. It's refreshing to see the traditional horizontal gaps between blocks disappear. (DIM did not like these.)

"Since Dias (2004, see references below) reckoned a periodic table is a partially ordered set forming a two-dimensional array, I believe I now have a partially ordered table that is partially disordered twice over.

"The table has some curious relationships. Equally, some relationships seen in the standard form are absent. The Group 2, 3, and aluminium dilemmas disappear. This confirms my impression that such dilemmas have no intrinsic meaning. Rather, their appearance or non-appearance is context dependent."

Notes & references below.

Groups 1 to 4 have either a C or F suffix where C (nonmetal) is after the importance of carbon to our existence; and F (metal) is for the importance of iron to civilisation.

Groups 1C and 1F present the greatest contrast in nonmetallic and metallic behaviour.

Coactive Nonmetals: They are capable of forming septenary heterogeneous compounds such as C20H26N4O10PSSe.

Group 2C: Helium is shaded as a noble gas. "Heliox" is a breathing gas mixture of helium and oxygen used in saturation diving, and as a medical treatment for patients with difficulty breathing.

Group 3C: Boron over nitrogen looks odd. Yet one boron atom and one nitrogen atom have the same number of electrons between them as two adjacent carbon atoms. The combination of nitrogen and boron has some unusual features that are hard to match in any other pair of elements (Niedenzu & Dawson 1965).

Boron and phosphorus form a range of ring and cage compounds having novel structural and electronic properties (Paine et al. 2005).

Metalloids. I treat them here as nonmetals given their chemistry is predominately that of chemically weak nonmetals.

Metals: The labels electropositive; transition; and electronegative are adapted from Kornilov (2008).

Group 1F: Monovalent thallium salts resemble those of silver and the alkali metals.

An alloy of cesium (73.71%), potassium (22.14%) and sodium (4.14%) has a melting point of –78.2°C (–108.76°F) (Oshe 1985).

Silver, copper, and gold, as well as being the coinage metals, are borderline post-transition metals.

Group 2F: Beryllium and magnesium are not in fact alkaline earths. Beryllium is amphoteric rather than alkaline; magnesium was isolated in impure form from its oxides, unlike the true alkaline earths. The old ambiguity over whether beryllium and magnesium should go over calcium or zinc has gone.

Nobelium is here since +2 is its preferred oxidation state, unlike other actinoids.

Group 3F: Aluminium is here in light of its similarity to scandium (Habishi 2010).

InGaAsP is a semiconducting alloy of gallium arsenide and indium phosphide, used in lasers and photonics.

There is no Group 3 "issue" since lanthanum, actinium, lutetium and lawrencium are in the same family.

Gold and aluminium form an interesting set of intermetallic compounds known as Au5Al2 (white plague) and AuAl2 (purple plague). Blue gold is an alloy of gold and either gallium or indium.

Lanthanoids: The oxidation state analogies with the transition metals stop after praseodymium. That is why the rest of lanthanoids are footnoted in dash-dot boxes.

Actinoids: The resemblance to their transition metal analogues falters after uranium, and peters out after plutonium.

Group 4F: It's funny to see titanium—the lightweight super-metal—in the same group as lead, the traditional "heavy" metal.

This is the first group impacted by the lanthanoid contraction (cerium through lutetium) which results in the atomic radius of hafnium being almost the same as that of zirconium. Hence "the twins".

The chemistry of titanium is significantly different from that of zirconium and hafnium (Fernelius 1982).

Lead zirconate titanate Pb[ZrxTi1–x]O3 (0 ≤ x ≤ 1) is one of the most commonly used piezo ceramics.

Group 5: Bismuth vanadate BiVO4 is a bright yellow solid widely used as a visible light photo-catalyst and dye.

Steel Friends: The name is reference to their use in steel alloys. They have isoelectronic soluble oxidizing tetroxoanions, plus a stable +3 oxidation state. (Rayner-Canham 2020).

Ferromagnetic Metals: The horizontal similarities among this triad of elements (as is the case among the PGM hexad) are greater than anywhere in the periodic table except among the lanthanides (Lee 1996). The +2 aqueous ion is a major component of their simple chemistry (Rayner-Canham 2020).

Group 8: "Rubiferous metals" (classical Latin rubēre to be red; -fer producing) is from the reddish-brown colour of rust; the most prevalent ruthenium precursor being ruthenium trichloride, a red solid that is poorly defined chemically but versatile synthetically; and the red osmates [OsO4(OH)4]?2 formed upon reaction by osmium tetroxide with a base.

Group 9: "Weather metals" comes from the use of cobalt chloride as a humidity indicator in weather instruments; rhodium plating used to "protect other more vulnerable metals against weather exposure as well as against concentrated acids or acids fumes" (Küpfer 1954); and the "rainbow" etymology of iridium.

Group 10: "Catalytic metals" is after a passage in Greenwood and Earnshaw, "They are... readily obtained in finely divided forms which are catalytically very active." (2002). Of course, many transition metals have catalytic properties. That said, if you asked me about transition metal catalysts, palladium and platinum would be the first to come to mind. Group 10 appear to be particularly catalytic.


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What is the Periodic Table Showing? Periodicity

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