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I am currently working on a periodic table to include it in a experimental chemistry book and I would like to include non-bonded atomic radii data so it would be easier for the students to learn about periodic trends and quickly determine if an atom is more likely to produce a hard or a soft Lewis acid-base.

The problem is that every reference I looked have different values for the same atom. For instance, see the results for Hydrogen and Gold non-bonded atomic radii below:

  1. In this site we have: 0.53 (H) / 1.74 (Au) Å
  2. In RSC site, we have: 0.32 (H) / 1.30 (Au) Å
  3. This aricle (Slater, 1964 - see the DOI below): 0.25 (H) / 1.35 (Au) Å
  4. Finally, in Wikipedia (which is the result Google will return if you type the search query "hydrogen/gold atomic radius") is: 0.53 (H) / 1.66 (Au) Å

These differences are observed in most elements. I do not know which one is more reliable. In my point of view, variations of 0.20 angstrons are too big in atomic scale, aren't they?

What do you think about what cause those variations? Are they significant? Could someone help me to find a reliable source for atomic radii data?

Maybe those variations occur due to statistical deviations from the method used to measure them, but could it be so big (about 20%)?

Thanks!

Slater, 1964. DOI: 10.1063/1.1725697

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    $\begingroup$ Forget it, there is no such thing. Atomic radii are inherently arbitrary and uncertain. Also, welcome to Chem.SE. $\endgroup$ – Ivan Neretin Jan 22 '17 at 19:03
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    $\begingroup$ There have been several attempts for systematic van der Waals and covalent radii sets using quantum mechanics and crystallography recently. But I find your particular request for "atomic" radii a bit unclear. Do you want VdW or covalent radii? $\endgroup$ – Geoff Hutchison Jan 22 '17 at 19:07
  • $\begingroup$ @IvanNeretin I see... I think it is so because the electron cloud has undefined edges. So do you think I should stick to one source or don't use a atomic radii data at all? $\endgroup$ – Guilherme Cruz Jan 22 '17 at 19:51
  • $\begingroup$ @GeoffHutchison I want to use these values in a periodic table for a didactic book, as I mentioned before. I am looking for the best atomic radii data for studying periodic trends related to size and consequently to Zef, such as, lanthanidic compression and hard and soft Lewis acid-base. I know that VdW is the best for noble gases since they aren't bonded to each other (except for Xe and Kr in some compounds). But I am not sure about what "radius" is best for the other elements: non-bonded, ionic or covalent? $\endgroup$ – Guilherme Cruz Jan 22 '17 at 20:00
  • $\begingroup$ Yes, exactly. Stick to some respectable source, remember that atomic radii are uncertain, maybe add a note to that effect. $\endgroup$ – Ivan Neretin Jan 22 '17 at 20:09

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