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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: 

  Text Search:       

Periodic Table database entries referencing the term electronegativity, by date:

1836   Berzelius' Electronegativity Table
1870   Baker's Electronegativity Table
1886   Discovery of Fluorine
1888   Stoney's Spiral Periodic Table
1893   Rang's Periodic Arrangement of The Elements
1895   Thomsen's Systematic Arrangement of the Chemical Elements
1923   Deming's Periodic Table With Commentry by Vernon
1960   Pauling's Complete Electronegativity Scale
1971   Satz's Reciprocal System Periodic Table
1987   Elsevier's Periodic Table of the Elements
1993   WebElements: The Periodic Table on The Web
2003   Electronegativity Periodic Table
2003   Electronegativity Periodic Table
2005   Extraction from Ore to Pure Element
2006   Where Should Hydrogen Go?
2006   Reaction Chemists' Periodic Table
2013   Electronegativity Chart (Leach)
2013   Top 10 Periodic Tables
2013   Averaged Ionisation Potential Periodic Table
2018   First Ionisation Energy to the Standard Form Periodic Table
2018   Acid-Base Behavior of 100 Element Oxides
2020   Correlation of Electron Affinity (F) with Elemental Orbital Radii (rorb)
2020   Vernon's Constellation of Electronegativity
2020   Vernon's (Partially Disordered) 15 Column Periodic Table
2021   Crustal Abundance vs. Electronegativity
2021   Electronegativity: A Three-Part Wave
2022   Electronegativity Seamlessly Mapped Onto Various Formulations of The Periodic Table
2022   99 Elements Sorted by Density & Electronegativity

Year:  1836 PT id = 453

Berzelius' Electronegativity Table

Berzelius' electronegativity table of 1836.

The most electronegative element (oxygen or Sauerstoff) is listed at the top left and the least electronegative (potassium or Kalium) lower right. The line between hydrogen (Wasserstoff) and gold seperates the predomently electronegative elements from the electropositive elements. Page 17 and ref. 32 from Bill Jensen's Electronegativity from Avogadro to Pauling Part I: Origins of the Electronegativity Concept, J. Chem. Educ., 73, 11-20 (1996):

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Year:  1870 PT id = 454

Baker's Electronegativity Table

Baker's electronegativity table of 1870 differs from Berzelius' listing of 1836 only by the addition of the newly discovered elements. Page 280 and ref. 5 from Bill Jensen's: Electronegativity from Avogadro to Pauling Part II: Late Nineteenth- and Early Twentieth-Century Developments, J. Chem. Educ., 80, 279-287 (2003):

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Year:  1886 PT id = 798

Discovery of Fluorine


Fluorine, atomic number 9, has a mass of 18.998 au.

Fluorine exists as a pale yellow diatomic molecular gas, F2. It is the most electronegative and reactive of all elements: it which reacts with practically all organic and inorganic substances.

Fluorine was first observed or predicted in 1810 by A.-M. Ampére and first isolated in 1886 by H. Moissan.

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Year:  1888 PT id = 1267

Stoney's Spiral Periodic Table

In the Proceedings of the Royal Society of London, Series A, Containing Papers of a Mathematical and Physical Character, Volume 85, Issue 580, Aug 1911, p. 472, there is an article On Dr. Johnstone Stoney's Logarithmic Law of Atomic Weights, by Lord Rayleigh (who co-discovered argon in 1894), who writes :

"In the year 1888, Dr. G. Johnstone Stoney communicated to the Society a memoir with title nearly as above, which, however, was not published in full. At the request of the author, who attaches great importance to the memoir, I have recently, by permission of the Council, consulted the original manuscript in the archives of the Society, and I propose to give some extracts, accompanied by a few remarks. The author commenced by plotting the atomic weights of the elements taken as ordinates against a series of natural numbers as abscissæ. But a curve traced through the points thus determined was found to be 'one which has not been studied by mathematicians.

"This sudden transition may have some connection with the fact that no elements have been found on sesqui-radius 16, although the investigation in § 3 shows that the values of m corresponding to the stations on sesqui-radius 16 cannot be dispensed with.

"The vacant places here pointed out are now occupied by the since discovered inert gases. The anticipation is certainly a remarkable one, and it goes far to justify the high claims made for the diagram, as representing in a telling form many of the leading facts of chemistry."

Comment from Mark Leach:

"Notice how the electronegative elements are positioned top right & bottom right and the electropositive elements top left & bottom right."

René Vernon writes:

"Stoney has another article in the September 1902 edition of the The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science, called Law of Atomic Weights, pp. 411–415. At the back of the journal is an updated fold-out version of Stoney’s table, image attached.

"On the page after the updated spiral, there looks to be some printed content, but it is hidden by what looks to be a folded over page."

Thanks to René for the tip!

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Year:  1893 PT id = 63

Rang's Periodic Arrangement of The Elements

P.J.F. Rang's The Periodic Arrangement of the Elements, Chemical News, vol. 67, p. 178 (1893)

Observing that that Rang's table has four 'groups': A, B, C & D, René Vernon writes:

    1. Group A contains the strongest positive elements; group D the strongest negative elements. At such an early date, it's odd to see groups 1 to 3 categorised together.
    2. Group B are the elements with high melting points; "they are all remarkable for their molecular combinations" (presuamably, a reference to multiple oxidation states). At one side of group B are the "anhydro-combinations", probably referring to the simple chemistry of Ti, Zr, [Hf] Nb and Ta being dominated by insoluble oxides. At the other side are the "amin, carbonyl, and cyanogen combination", probably a reference to the group VIII carbonyls, as metal carbonyls had only just been discovered. Ni is shown after Fe, rather than Co.
    3. Group C includes the "heavy metals that have low melting points"; an early reference to frontier or post-transition metals, as a category.
    4. Rang says: ...if groups A and D be split up vertically in respectively three and two parts, the table presents seven vertical groups, and horizontally seven more or less complete series. Each group in each of the series 2 and 3 are represent by one element... The octave appears both horizontally and vertically in the table.
    5. Rang's reference to Di as representing all the triads between Ba and Ta kind of works since Hf would go under Zr, and that would leave 15 Ln or five sets of three. Thus, something like this:

      Gd occupies the central position among the Ln. This arrangement won't fit however unless Rang envisaged all 15 Ln occupying the position under Y.
    6. The location of H over | Ga | In | Tl, appears strange... but the electronegativity of H (2.2) is closer to B (2.04) than it is to C (2.55).

From Quam & Quam's 1934 review paper.pdf

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Year:  1895 PT id = 368

Thomsen's Systematic Arrangement of the Chemical Elements

In 1895 the Danish thermochemist Hans Peter Jørgen Julius Thomsen proposed (Thomsen, J., 1895. Z. Anorg. Chem. 9, 190 & Chemical News, 72, 89–91, p. 90) a pyramidal/ladder representation.

Notice how this formulation identifies the electropositive & electronegative elements with respect to the periodic table, thirty years before Linus Pauling.

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Year:  1923 PT id = 1256

Deming's Periodic Table With Commentry by Vernon

René Vernon writes:

Deming's 1923 periodic table is credited with popularizing the 18-column form.

I now see Deming used different thickness sloping lines to represent the different degrees of similarity between the main groups and their corresponding transition metal groups.

When I plot up to 20 chemical properties v Z going down these options I get the following values for the average smoothness of the trendlines:

I would have thought the smoothness for the line between Li-Na and Cu would be < 70%, consistent with Deming’s dashed line. But the thickness of the line would depend on what Deming took into account when he drew it. The common wisdom about groups 1 and 11 is that their similarities are: "confined almost entirely to the stoichiometries (as distinct from the chemical properties) of the compounds in the +1 oxidation state." (Greenwood & Earnshaw 2002, p. 1177). Kneen et al. (1972, p. 521) say that, "the differences between the properties of the group IA and IB elements are those between a strongly and weakly electropositive metal." On this basis I follow Deming’s dashed line. I’ve appended some notes about Group 1 and Group 11.

I have [calculated] a smoothness for C-Si-Ti-Zr-Hf of 86% versus 70% for C-Si-Ge-Sn-Pb. Since Ti shows some transition metal chemistry but not C-Si, it is perhaps plausible to keep C-Si-Ge-Sn-Pb together (as Deming did ).

Deming was a smart author. Nigh on a century later and the metrics check out.

More about group 1 and group 11

There may be a little more to the relationship between Li-Na & Cu-Ag-Au, than is ordinarily appreciated. For example:


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Year:  1960 PT id = 444

Pauling's Complete Electronegativity Scale

From The Nature of The Chemical Bond, 3rd Ed, pp 93, Pauling gives a periodic table showing the electronegativity of the elements.

Notice how the d block appears between groups 3 and 4 (13 & 14), rather than between groups 2 and 3 (2 & 13):

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Year:  1971 PT id = 205

Satz Reciprocal System Periodic Table

Developed in 1971 for my book The Unmysterious Universe, this periodic table is based on Dewey B. Larson's Reciprocal System of theory. The numbers below the symbols indicate the rotational displacement (spin numbers) of the atoms.  The Roman numerals indicated divisions; the rows, 1B to 4B, are referred to as "groups" rather than as "periods."  Note that we have the same trouble positioning hydrogen as does everyone else; here, I've put it over both the alkali metals and the halogens, because it acts both as electropositive (e.g., with respect to water) and electronegative (with respect to carbon).

Click here for larger PDF file.

Ronald W. Satz, Ph.D.
Transpower Corporation

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Year:  1987 PT id = 743

Elsevier's Periodic Table of the Elements

Prepared by P. Lof is Elsevier's Periodic Table of the Elements.

This educational wall chart features the periodic table of the elements supported by a wealth of chemical, physical, thermodynamical, geochemical and radiochemical data laid down in numerous colourful graphs, plots, figures and tables. The most important chemical and physical properties of the elements can be found - without turning a page.

All properties are presented in the form of tables or graphs. More than 40 properties are given, ranging from melting point and heat capacity to atomic radius, nuclear spin, electrical resistivity and abundance in the solar system. Sixteen of the most important properties are colour coded, so that they may be followed through the periodic system at a glance. Twelve properties have been selected to illustrate periodicity, while separate plots illustrate the relation between properties. In addition, there are special sections dealing with units, fundamental constants and particles, radioisotopes, the Aufbau principle, etc. All data on the chart are fully referenced, and S.I. units are used throughout.

Designed specifically for university and college undergraduates and high school students, "Elsevier's Periodic Table of the Elements" will also be of practical value to professionals in the fields of fundamental and applied physical sciences and technology. The wall chart is ideally suited for self-study and may be used as a complementary reference for textbook study and exam preparation.

Thanks to Eric Scerri for the tip!
See the website and Eric's Twitter Feed
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Year:  1993 PT id = 114

WebElements: The Periodic Table on The Web

Mark Winter's WebElements was started in 1993 when it was one of the first websites on the internet.

Mark Leach's Chemogenesis web book uses the WebElements periodic table as its master data source, and it does not attempt to duplicate it.

Abundance of elements (Earth's crust)
Abundance of elements (oceans)
Abundance of elements (sun)
Abundance of elements (Universe)
Abundance of elements (in human body)
Accurate mass of the isotopes
Atomic number
Atomic weight
Biological role
Block in periodic table
Boiling point
Bond enthalpy (diatomics)
Bond length in element
Colour (color)
Covalent radius
Crystal structure
Electrical resistivity

Electronic configuration
Element bond length
Enthalpy of atomization
Enthalpy of fusion
Enthalpy of vaporization
Examples of compounds
Group name numbers
Health hazards
History of the element
Ionic radius
Ionization energy
Isotope data
Key data
Meaning of name
Melting point
Molar volume
Names and symbols
Nuclear data
Origin of name

Oxidation states in compounds
Period in table
Properties of some compounds
Radius (atomic)
Radius (covalent)
Radius (ionic)
Radius (van der Waals)
Radius metallic (12)
Radioactive isotopes
Resistivity (electrical)
Shell structure
Standard atomic weights
Standard state
Structure of element
Thermal conductivity
Van der Waals radius
X-ray crystal structure

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Year:  2003 PT id = 311

Electronegativity Periodic Table

"This image distorts the conventional periodic table of the elements so that the greater the electronegativity of an atom, the higher its position in the table", here:

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Year:  2003 PT id = 123

Electronegativity Periodic Table

A periodic table showing electronegativity, "The ability of an atom to attract electron density from a covalent bond" (Linus Pauling). Blue elements are electronegative, red elements are electropositive, and purple elements are intermediate. Notice how hydrogen is intermediate in electronegativity between carbon and boron and is positioned above and between these elements:

By Mark Leach

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Year:  2005 PT id = 137

Extraction from Ore to Pure Element

A periodic table showing how pure elements are extracted:

Highly electropositive elements (Na, K) and electronegative elements (Cl2, F2) can only be obtained by electrolysis.

By Mark Leach

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Year:  2006 PT id = 17

Where Should Hydrogen Go?

There are four possible positions for hydrogen:

By Mark Leach

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Year:  2006 PT id = 56

Reaction Chemists' Periodic Table

OK, so which Is The Best formulation of The Periodic Table?

Personally as a reaction chemist, my preferred periodic table is the 'long' form shown below, with hydrogen above and between boron and carbon, although clearly other scientists have other ideas.

All periodic tables show the increase in mass and atomic number, Z, but only the long form unambiguously shows the general top-right-to-bottom-left trends in electronegativity, atomic radius, metallic properties and first ionisation energy.

Electronegativity is absolutely crucial to the understanding of structure, bonding, material type (van Arkel-Ketelaar triangle and Laing tetrahedron) and chemical reactivity, and it underpins much of the chemogenesis analysis.

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Year:  2013 PT id = 566

Electronegativity Chart (Leach)

From Mark R Leach's paper, Concerning electronegativity as a basic elemental property and why the periodic table is usually represented in its medium form, Journal & PDF.

Due to the importance of Pauling's electronegativity scale, as published in The Nature of The Chemical Bond (1960), where electronegativity ranges from Cs 0.7 to F 4.0, all the other electronegativity scales are routinely normalised with respect to Pauling's range.

When the Pauling, Revised Pauling, Mulliken, Sanderson and Allred-Rochow electronegativity scales are plotted together against atomic number, Z, the similarity of the data can be observed. The solid line shows the averaged data:

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Year:  2013 PT id = 610

Top 10 Periodic Tables

There are more than 1000 periodic tables hosted by the Chemogenesis Webbook Periodic Table database, so it can be a little difficult to find the exceptional ones.

Here we present – in our humble opinionThe ten most significant periodic tables in the database.

We present the best:

Three Excellent, Data Rich Periodic Tables

The first three of our top 10 periodic tables are classic element data repositories.

They all work in the same way: click on the element symbol to get data/information about the selected element. The three are Mark Winter's WebElements, Theo Gray's Photographic Periodic Table & Michael Dayah's Ptable.

<Web Elements>

Photographic Periodic Table


Five Formulations Showing The History & Development

The next five examples deal with history and development Periodic Table. The first is Dalton's 1808 list of elements, next is Mendeleev's 1869 Tabelle I, then Werner's remarkably modern looking 1905 formulation. This is followed by Janet's Left Step formulation and then a discussion of how and why the commonly used medium form PT formulation, is constructed.

<Eight-Group Periodic Table>

Mendeleev's Tabelle I

Werner's 1905 Periodic Table

Janet's Left Step

modern (and commonly employed) periodic table

electronegativity periodic table

An Alternative Formulation

The internet database contains many, many alternative formulations, and these are often spiral and/or three dimensional. These exemplified by the 1965 Alexander DeskTopper Arrangement. To see the variety of formulations available, check out the Spiral & Helical and 3-Dimensional formulations in the database:

Alexander DeskTopper Arrangement

Non-Chemistry PTs

The periodic table as a motif is a useful and commonly used infographic template for arranging many types of object with, from 50 to 150 members.

There are numerous examples in the Non-Chemistry section where dozens of completely random representations can be found:

Non-Chemistry Periodic Table

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Year:  2013 PT id = 619

Averaged Ionisation Potential Periodic Table

By Leland Allen, a representation of the periodic table with the third dimension of energy derived from the averaged ionisation potentials of the s and p electrons. (Allen suggested that this was a direct measure of electronegativity). From J. Am. Chem. Soc. 1989, 111, 9004:

Averaged Ionisation Potential

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Year:  2018 PT id = 774

First Ionisation Energy to the Standard Form Periodic Table

There is debate amongst the cognoscenti about the 'best' representation of the periodic table, and how this 'best' formulation can be explained by [rationalized by] quantum mechanics (QM).

Many feel that the Janet PT formulation, the 'Left Step', is the ideal QM PT, but this formulation does not show periodicity very well, and there are issues with the placement of H, He, Be which spill over into questions about their placement in the standard form PT (the periodic table used in classrooms and textbooks around the world).

However, it is possible to get to the conventional standard form PT directly from the first ionisation energy data, where the 1st ionisation energy is the energy required to convert a gas phase atom (M) into its gas phase positive ion plus electron.

M(g)      →       M+(g)     +     e

The process involves:


Note that a similar logic can be applied to atomic radius and electronegativity data.

However, there are issues about the measurement of atomic radius, because atoms are 'soft at their edges', and gas phase atomic radius is not precisely defined. And, electronegativity is a derived parameter.

By Mark Leach

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Year:  2018 PT id = 929

Acid-Base Behavior of 100 Element Oxides

Acid-Base Behavior of 100 Element Oxides: Visual and Mathematical Representations by Mikhail Kurushkin and Dmitry Kurushkin. J. Chem. Educ.  95, 4, 678-681.

A novel educational chart that represents the acid-base behavior of 100 s-, p-, d-, and f-element oxides depending on the element's electronegativity and oxidation state was designed. An updated periodic table of said oxides was developed. A mathematical criterion based on the chart was derived which allows prediction of the behavior of unfamiliar oxides:

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Year:  2020 PT id = 1117

Correlation of Electron Affinity (F) with Elemental Orbital Radii (rorb)

From Jour. Fac. Sci., Hokkaido Univ., Ser. IV. vol. 22, no. 2, Aug., 1987, pp. 357-385, The Connection Between the Properties of Elements and Compounds; Mineralogical-Crystallochemical Classification of Elements by Alexander A. Godovikov & Yu Hariya and expanded by René Vernon who writes.

René Vernon writes:

I was delighted to read about two properties that account for nearly everything seen in the periodic table.

Two properties
While researching double periodicity, I happened upon an obscure article, which simply correlates electron affinity with orbital radius, and in so doing reproduces the broad contours of the periodic table. Having never thought much about the value or significance of EA, and its absence of easily discernible trends, I was suitably astonished. The authors left out the Ln and An and stopped at Bi. They were sitting on a gold mine but provided no further analysis.

I added the data up to Lr, updated the EA values, and have redrawn their graph. It is a thing of beauty and wonderment in its simplest sufficient complexity and its return on investment. I've appended 39 observations, covering all 103 elements.


So there it is, just two properties account for nearly everything.

Click images below to enlarge:

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Year:  2020 PT id = 1122

Vernon's Constellation of Electronegativity

René Vernon has created a "Constellation of Electronegativity" by plotting Electronegativity against Elemental Orbital Radii (rorb)

Observations on the EN plot:

    1. The results are similar to the orbital radii x EA plot, although not quite as clear, including being more crowded
    2. Very good correspondence with natural categories
    3. Largely linear trends seen along groups 1-2, 17 and 15-18 (Ne-Rn)
    4. First row anomaly seen for He (or maybe not since it lines up with the rest of group 2)
    5. For group 13, the whole group is anomalous
    6. For group 14 , the whole group is anomalous no doubt due to the scandide contraction impacting Ge and the double whammy of the lanthanide and 5d contraction impacting Pb
    7. F and O are the most corrosive of the corrosive nonmetals
    8. The rest of the corrosive nonmetals (Cl, Br and I) are nicely aligned with F
    9. The intermediate nonmetals (IM) occupy a trapezium
    10. Iodine almost falls into the IM trapezium
    11. The metalloids occupy a diamond, along with Hg; Po is just inside; At a little outside
    12. Rn is metallic enough to show cationic behaviour and falls into the metalloid diamond
    13. Pd is located among the nonmetals
    14. The proximity of H to Pd is again (coincidentally?) curious given the latter's capacity to adsorb the former
    15. The post-transition metals occupy a narrow strip overlapping the base of the refractory metal parallelogram
    16. Curiously, Zn, Cd, and Hg (a bit stand-off-ish) are collocated with Be, and relatively distant from the PTM and the TM proper
    17. The ostensibly noble metals occupy an oval; curiously, W is found here; Ag is anomalous given its greater reactivity; Cu, as a coinage metal, is a little further away
    18. Au and Pt are nearest to the halogen line
    19. The ferromagnetic metals (Fe-Co-Ni) are colocated
    20. The refractory metals, Nb, Ta, Mo, W and Re are in a parallelogram, along with Cr and V; Tc is included here too
    21. Indium is the central element of the periodic table in terms of mean orbital radius and EN; Tc is next as per the EA chart
    22. The reversal of He compared to the rest of the NG reflects #24
    23. All of the Ln and An fall into an oval of basicity, bar Lr
    24. The reversal of the positions of Fr and Cs is consistent with Cs being the most electronegative metal
    25. A similar, weaker pattern is seen with Ba and Ra. 

Click to enlarge:

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Year:  2020 PT id = 1165

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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Year:  2021 PT id = 1183

Crustal Abundance vs. Electronegativity

A chart by René Vernon of Elemental Abundance (g/kg log10) vs. Electronegativity, H to Bi.

René writes:

Below is a remarkable XY chart where x = electronegativity and y = crustal abundance (log10). It stops at the end of the s-process, at Bi. The abundance figures are from the CRC Hanbook of Physics and Chemistry (2016-2017).

I say remarkable as I had little idea what the chart would end up looking like when I started plotting the values.

As well as its coloured regions, I've marked out track lines for six of the main groups and one for group 3.


The rose-coloured arc on the left encompasses the pre-transition metals i.e. the alkali and alkaline earth metals and aluminium, followed by, in the orange rectangle, the rare earth metals. Opposite these regions, along the southern boundary of the green paddock, are the halogens.

In the pale yellow field sheltered by the pre-transition metals and the REM, are the 3d transition metals and, in the white corral, are 4d and 5d base transition metals. Opposite these regions, in the green paddock, are the core nonmetals H, C, N, O, P and S, with Se as an outlier.

Following in the grey blob are the post-transtion or poor metals, immediately adjacent to the bulk of the metalloids or poor nonmetals.

Finally, in the light blue patch, the noble metals are complemented by the noble gases frolicking in the open.

Abundance tends to decrease with increasing Z. Notable exceptions are Li, B, N and Si.



I was intrigued by the article referring to Ni and Ar, and the suggestion of Ar becoming somewhat anionic, albeit in extreme conditions (140 GPa, 1500 K)



I wasn't looking for these but they at least exist as follows:

My references are:

Thus the abundance of the metals in the crust tends to fall with increasing EN.

An answer from L. Bruce Railsback, creator of the Earth Scientist's Periodic Table

"I think I can answer one of the questions. 'Why is Si good at forming a planetary crust?' – because it's so bad at staying in the core. Silicon isn't sufficiently metallic to stay in the core. Even in the mantle and crust, it doesn't go into non-metal solids well: in cooling magmas, it's only a lesser member of the early-forming minerals (e.g., Mg2SiO4, forsterite, where it's outnumbered two to one). The mineral only of Si as a cation, SiO2 (quartz), is the LAST mineral to form as a magma cools, in essence the residuum of mineral-forming processes. At least some this thinking is at Bowen's Reaction Series and Igneous Rocks at"

Which Electronegativity Scale?

The wide variety of methods for deriving electronegativities tend to give results similar to one another.

Click to enlarge:

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Year:  2021 PT id = 1190

Electronegativity: A Three-Part Wave

René Vernon points out that although there is a general trend in increasing electnegativity from Cs to F, there is actually an s-curve in the data.

Electronegativity across groups 1 to 18 appears to a show a three-part wave-like pattern.

There is a rise from group 1 to group 6, followed by a fall at group 7. I guess for group 7 that the EN for Mn is based on +2 and in this state Mn has five 3d electrons. The EN for Tc and Re are presumably based on +7, in which they notionally have underlying [Kr] and [Xe] cores.

There is rise from 7 to 8 (why?); a mesa from 8 to 11 (why?) that includes the PGM; and a fall at group 12. The fall may be influenced by group 12 having a full d shell; ditto group 13.

There is a rise from 13 to 18. Whereas in group 13 there is ionic chemistry in the form of the cations of Al to Tl this is not the case for C, Si, and Ge in group 14. Sn is reluctant to form a cation expect at pH < 1, and there is no Pb4+ cation.

The R2 value of 0.9739 is a best fit value for a second order polynomial. R2 for a straight line is 0.786

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Year:  2022 PT id = 1241

Electronegativity Seamlessly Mapped Onto Various Formulations of The Periodic Table

A discussion on the Google Groups Periodic Table Discussion List, involving a René Vernon, Nawa Nagayasu & Julio Samanez (all contributors this database) lead to the development of the representations below, showing electronegativity seamlessly mapped onto a modified Left-Step Periodic Table:

Nawa Nagayasu has mapped electronegativity to Mendeleeve's formulation:

Nawa Nagayasu has mapped electronegativity onto other formulations, Julio's Binode Spiral:

Courtine's 1926 formulation:

and the "conventional", short, medium and long forms of the periodic table with hydrogen above and between B & C which show the botom-right-to-top-left electronegativity trend:

Jeff Moran's Spiral:

René Vernon's 777 Periodic Wedding Cake:

Valery Tsimmerman's ADOMAH formulation:

Valery Tsimmerman's ADOMAH tetrahedron (in a glass cube) formulation:

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Year:  2022 PT id = 1254

99 Elements Sorted by Density & Electronegativity

René Vernon writes:

"A little while I ago I noticed that a scatter plot of EN (revised Pauling) and density values of the elements resulted in a nice distribution, as per the table below.

"According to Hein and Arena (2013) nonmetals have low densities and relatively high EN values; the table bears this out. Nonmetallic elements occupy the top left quadrant, where densities are low and EN values are relatively high. The other three quadrants are occupied by metals. Of course, some authors further divide the elements into metals, metalloids, and nonmetals although Odberg argues that anything not a metal is, on categorisation grounds, a nonmetal.

Note 25 says:

(a) Weighable amounts of the extremely radioactive elements At (element 85), Fr (87), and elements with an atomic number higher than Es (99), have not been prepared.
(b) The density values used for At and Fr are theoretical estimates.
(c) Bjerrum (1936) classified "heavy metals" as those metals with densities above 7 g/cm^3.
(d) Vernon (2013) specified a minimum electronegativity of 1.9 for the metalloids.

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