Iron-56; 126 pm (picometers = 10^-12 meters) Atomic Radius and allotropes

Iron-56; 126 pm (picometers = 10^-12 meters) Atomic Radius and allotropes

Originally Published on: Dec 18, 2015 @ 09:45

When I published here my ‘New Tectonics’ series last year, I took some old chemistry and physics books I have at home, and searched the Internet for further data.

Data that usually one has to be a technician on the specific matters to know that far, because, generally speaking, information on texts books of General Chemistry (I mean those for University), don’t plunge too much into certain properties. For which I will put here some links, in order to let you see how many inaccuracies there are regarding some topics, and particularly those of the 8B traditional group of the elements, or groups 8, 9, and 10, among which iron (Fe-56 in its most stable and abundant form),  is situated.

Atomic radii tables images

I’ll put this other link which presents some different tables regarding this property of the elements.

Some specific properties of iron and its isotopes.

An isotope of an element has differences in mass, must not be mistaken with an allotrope, and talking about iron-56, I’ll provide this link for you to read as I go on writing this DRAFT about Fe-56 allotropes (beware of mistakes that might be provided by en.wikipedia links inside this article).

Allotropy is a trheedimensional property: has lenght, width, and depth, and is the property that depends on how atoms are differently arranged in threedimensional space (if they were notes for a music, well, the same quaver type note can be differently positioned on the score page to get different rhythms and pitches).

And here starts my last year’s analisys on the element iron for its most abundant isotope iron-56 allotropes:

Depending on pressure and temperature iron-56 has (at least) five allotropic forms, being these:

  1. (alpha) α-iron, with a bcc, body centered cubic structure (such as that of NaCl, salt at the see).
  2. (betha) β-iron. They are two indeed, but pass to only one, these two, along with the rest of allotropes, I’ll explain better later ((x2) hcp,  double hexagonal CLOSE-packed | orthorhombic.
  3. (gamma) γ-iron, with an fcc, face centered cubic structure (austenite).
  4. (delta) δ-iron, with a bcc structure.
  5. (epsilon) ε-iron, with a hcp (hexagonal close-packed) structure.
  6. further iron-56 isotopes to discover.
  7. Either of the bullet 2:orthorhombic, or (x2) hexagonal close-packed.

These allotropes of iron-56, that is to say, Fe, alone, as the average Joe knows it, that element in the IUPAC table of a ponderate mass of 55,845 (this is because in the periodic table of the elements there are decimal numbers for atomic masses, being these decimal numbers the result of the proportional of all isotopes of an element and its relative abundancies, among who in the case of iron, 56 is its most abundant isotope), form at increasing temperatures ranges from alpha to epsilon (and higher or lower temperatures considering the isotopes neither I, nor chemists  have found).

And also at different pressures, producing the bullet #2, in this list I wrote above varieties (x2)hcp, and orthorhombic, and also bullet #3 (austenite),face centered cubic, at very high pressures:

‘The effect of hydrostatic pressure up to 20 kbar on the austenite start temperature, As of an Fe-30.3 wt.% Ni alloy has been measured in detail. An exceptionally large pressure coefficient of ≥ 30°C/kbar is observed up to 2.3 kbar; from 2.3 to 6 kbar As is observed to increase with pressure, while from C to 20 kbar As is observed to decrease at a rate of −1.9°C/kbar. A model based on the difference in compressibilities of the martensite and austenite phases is proposed to explain these results. Cold working by rolling prior to the application of hydrostatic pressure shifts the general features of the non-cold worked Asvs pressure curve to higher pressure and to higher temperature. It is argued that these observations give very strong evidence that martensite reversal initiates at the martensite-austenite interface. Similar studies were also made on Fe-29.1 wt.% Ni-1 wt.% Co and Fe-30.4 wt.% Xi-2 wt.°% Mn ternary alloys. These results indicate that the character of the martensite reversal (athermal vs. isothermal) may affect the dependence of As on hydrostatic pressure.’

excerpt from sciencedirect webpage.’

with two additional links where you can find more information, note that any of the 3-D representations for unit cells are orthogonal, but not all of them are orthonormal, meaning this different distributions of lenghts, areas, volumes, for their vector bases and moduluses, along with their shapes also.

All isotopes (with their allotropes) of iron, are highly ferromagnetic (see note below), meaning this, that iron is strongly affected by magnetic fields, and also that magnetic fields affect strongly iron, this is why iron (and alloys) are used in computers whose magnetic storing peripherals, such as hard disks drives (be it at home or ‘in the cloud’) are mainly made of ferrites.

Hullabaloo link to isotopes definition(to be clarified by me afterwards, it is quite a long dehullabaloozation to do…).


Note: the words ferrite and ferromagnetic comes from ferrum, a latin word for iron, and magnetic.

I’ll stop here, and will continue writing this DRAFT later, beware of changes before this sentence and after.

[21st December update]

Fortunately there are more chemistry experts in the world who have already systemated some tables, so, I’ll provide this link to en.wikipedia where you can read the daughter isotopes and decay modes (I wrote also on decay, decaimiento, already to explain it in a simpler way).

So, taking gamma, -beta, and +beta decays (specially beta because of its not quantized spectrum nature, though any other decay type would do, for which you can search in the link above), starting with [Fe-54] and ending with [Fe-60], we have daughter isotopes of [Mn-54] ~= [Cr-54], Mn-55, and Ni-58 to [Ni-60], Cu-63, Zn-66, and their isotopes, passing all the way through the IUPAC recognized most stable isotopes for each element, that I will write here for the sake of convenience.

[Contained in the 6 and 7 orbitals in my table, that’s the 6th and 7th rows starting from top hidrogene, helium, s like IUPAC orbital (= probability region for the electrons), the [CAPITAL] S orbital in my table’s model, I have a 5 periods, with their 15 sub-levels increasing by one and the elements growing from the center in mass, evens on the right and odds on the left, and 16 groups structure in my table (+ 4, REMEMBER those who have a different icon in my table are synthetic elements) which differs from the 7 periods and 18 groups of the IUPAC’s by all (?) known table [ 🙂 ].

(Which, by the way, I wrote joining two DIN A4 sheets of paper, in big squares, with their electrons ordering, mass ordering and the sum of both and I must check sometimes in order to know some elements masses and positions, don’t think about what I would do having some 3-D sets of models for atoms and molecules… 🙂 ).



Chromium: [Cr-54],

Manganesum: Mn-55,

Ferrum| Iron: Fe-56,

Cobalt: Co-59,

Cuprum | Copper: Cu-63,

Zinc: Zn-66

And also according to my table: Vanadium, Scandium, Potasium, Calcium, and Titanium, for which you yourselves can search the IUPAC defined properties.

I’ll add my table below, which you can view bigger and better by opening it in a separate tab | window.



NOTE: The symbols for Uus, and Uuo, did not fit entirely in the area, so I bent the line which is below the last row (sub-level), of elements, where Berkelium and Californium are, and encompasses these two elements, Ununseptium (see December the 26th update below, in which I comment some aspects of this element), and Ununoctium, also, but they belong to my fifteenth sub-levels model, I put them that way also because them two (along with the rest which have a different icon, and Kurziatovium, and Hasnium) are synthetic, that is to say, they were obtained by bombarding inside an accelerator, such as CERN, or others alike.

And today’s update ends here.

December the 22nd update

I will only put here an image for one  of the tables in which I superimposse the circles aproximately proportional to the radii. The circles and values for radii of the elements were reordered by me upon my table using the values of this webpage (beware of the intermediate La to Hf (this last considered a metal traditionaly), Lantanides, and all the Actinides missing in the link’s table [General Chemistry], which not being there I didn’t put on my table in the image below, image I provide, but to be improved later).

[You know? there are more than 106 elements in the IUPAC table… 🙂 ].


Original image from the webpage in the link averillfwk-fig07_007

Reordering in other version resolution

My reordering

my ordering for atomic radii

My reordering for atomic radii in other version

[December the 25th 2015 update (Happy Christmas!)]

Today I will upload some crops I’ve just made from a Spanish webpage on Chemistry whose name you can see in my browser’s address bar, for the four elements I put into a blue rounded rectangle, of whom I wrote the text in the blue rounded-corner square rectangle in the image above, in which I said I considered other positions for these four elements, but if you consider all I did, you will end up putting them there too.

Silver, Ag, Cadmium, Cd, Europium, Eu, and Gadolinium, Gd. For Gd, I include also a crop from the en.wikipedia into which its Curie’s temperature (that temperature point that passing above or below affects the magnetic behaviour of the elements), has a value in Kelvin degrees very different from that same value given in the Spanish webpage (that has a button to translate itself).

This discrepancy in Curie’s temperature for Gadolinium is important, being in on case minus -257 º Centigrade (very near to 0 Kelvin; and according to the value in the crop of the webpage, 16º Kelvin), and in the other case 293.4 º Kelvin, which in Centigrade are 20.4º C being in this latter case ambiance temperature here and in most places on Earth. And in Kelvins |293.4 -16| = |277.4| .











Along with these four elements, I will include also two more crops for Radon and Xenon, both into the 18th group for noble gases, and consecutive levels in IUPAC’s table, but both forming natural compounds, being thus a bit less noble-gases-like elements. These two you can see one column displaced on the right in my ordering, not in a corner (although them both are next to an edge of the green-orange areas in my table, and on the orange area) as opossed to the cases for He, Ne, Ar, and Kr.





And to end today’s update, one image on 3D distributions in alloys (to be deployed and better explained in forthcoming updates) and some more links.

Gibbs energía interna

Gibbs energía interna

From this link watch the IV A section pdf.

[December the 26th update]

I’ll add here an excerpt from en.wikipedia article on Ununseptium for which I put the link above right under the image of my table, and then I’ll make you notice some more aspects of my reordering (I think I already told you, but I’ll say it once more: I had 35 criteria on account while reordering the elements in my chart).

In January 2010, scientists at the Flerov Laboratory of Nuclear Reactions announced internally that they had detected the decay of a new element with atomic number 117 via two decay chains:

  1. one of an odd-odd isotope undergoing 6 alpha decays before spontaneous fission,
  2. and one of an odd-even isotope undergoing 3 alpha decays before fission.[18]

On April 9, 2010, an official report was released in the journal Physical Review Letters identifying the isotopes as 294Uus and 293Uus, which were shown to have half-lives on the order of tens or hundreds of microseconds.

Excerpt from en.wikipedia (I included the bold and bulleted list for the sake of clarity).

If you take my table and you go six sub-levels upwards from the fifteenth sub-level, you get to the level 3, sub-level nine in my model, right above the position for Cs, Caesium (or if you start counting from Caesium downward starting from Rhodium), you get to the Ununseptium position. This complies with #1 bullet.

If you go three positions on the left from Roentgenium, Rg, in the last row from the light gray area where I put my fourth sub-level orbital (present in the 4th and 5th levels in my model), and which has 16 instead of 14, and I called, [Capital] G orbital in my model, where Berkelium and Californium are, you get to Ununseptium also.

But, these further positions which go out of my 16 possible locations for electrons, three on the left, three on the right, can also be in another places below that last row, in which case there would be a sixteenth sub-level, aspect I strongly recommend not to go on investigating nor developing, and this is why it looks like that in my table.

Remember Berkelium and Californium are synthetic too.

I’ll finish this post here, and will go on explaining on Iron-56, which is what I am explaining, in a second post with the (II) after the same title for this post.

Acerca de María Cristina Alonso Cuervo

I am a teacher of English who started to write this blog in May 2014. In the column on the right I included some useful links and widgets Italian is another section of my blog which I called 'Cornice Italiana'. There are various tags and categories you can pick from. I also paint, compose, and play music, I always liked science, nature, arts, language... and other subjects which you can come across while reading my posts. Best regards.
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