[Wien] calculating Ionic charge

[Laurence Marks]

They did not calculate the "ionic charge", they assumed it. The
closest you can come in something you calculate is the
bond-valence-sum (which you can approximately get using "x nn"), see
(for instance)

Surface Science 606, 344 (2012)
I.D. Brown, D. Altermatt, Acta Crystallographica Section B-Structural
Science 41 (1985).
I.D. Brown, The chemical bond in inorganic chemistry : the bond
valence model, Oxford ; New York, Oxford University Press, 2002.
I.D. Brown, Chemical Reviews 109 (2009).
L. Pauling, Journal of the American Chemical Society 51 (1929) 1010.
R.F.W. Bader, Chemical Reviews 91 (1991).
I.D. Brown, Acta Crystallographica Section B-Structural Science 48 (1992).


On Tue, Feb 21, 2012 at 1:09 PM,  <puday at iitk.ac.in> wrote:
> Dear Wien2k users
> Can anyone tell me how to calculate the ionic charge for an atom inside
> unitcell?
> I will give you an example which is published on PRB
> PHYSICAL REVIEW B 79, 054510 (2009)
> They have calculated "Ionic charge" and "Bader" charge for individual
> atoms in the compound "LaOFeP" which is listed bellow
>
> ------------------------------------------------
> Atom      Purely Ionic charge    Bader Charge
>      (using purely ionic model)
> ------------------------------------------------
> La   =     8 (La^3+)              9.05
> O    =     8 (O^2-)               7.31
> Fe   =     6 (Fe^2+)              7.59
> P    =     8 (P^3-)               6.05
> -----------------------------------------------
>
> I don't understand how to calculate the ionic charge using "purely ionic
> model" for example 8 of La^3+ ion as listed above.
> Please help me.
>
> Regards,
> Uday Bhanu Paramanik
> Dept.of Physics
> IIT Kanpur
> India
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-- 
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi