Talk:Kapustinskii equation

Latest comment: 15 years ago by Jimp in topic Coefficients

Assumptions/Derivation from Born-Landé equation

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I've got a list of three assumptions used to form the Kapustinskii equation from the Born-Landé equation in my first-year undergraduate lecture notes (handwritten by me, so no copyright issues). Shall I put them up to improve the article? Brammers (talk) 15:23, 30 April 2009 (UTC)Reply

Coefficients

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The equation is given thus (delinked).

 
... It is important to remember that the units of the radii in this equation are Ångström, and the lattice energy is given in kJ/mol.

It's more usual to write something like

 

and then define the constants a & b in terms of appropriate units. The question is what we should use as coefficients, a & b or something else. We then don't have to "remember" to use these units or those.

Looking at this, K and d seem decent labels for the coefficients.

We thus get:

 
where K = 1.2025×10−4 J·m·mol−1
d = 3.45×10−11 m
ν is the number of ions in the empirical formula,
z and z+ are the numbers of elementary charge on the anion and cation, respectively, and
r and r+ are the radii of the anion and cation, respectively.

JIMp talk·cont 22:10, 24 June 2009 (UTC)Reply