Talk:Solvation shell

Solvation number
I see that some section containing a calculation of the solvation number has been removed due to being unreferenced. I think a cn tag could have been placed instead of removing the useful content.--85.121.32.1 (talk) 08:42, 8 August 2016 (UTC)
 * Please see WP:BURDEN. Do not restore unsourced content without adding a source.  I've pasted it below. Jytdog (talk) 00:33, 14 August 2016 (UTC)

Unsourced
The following is unsourced. Cut from article and pasted here per V

The solvation number could be determined from the compressibility of the solvent and solution. $$n_s = (1 - \frac {\beta}{\beta_0}) \frac{n_i}{n_0}$$
 * Solvation number

where $$\beta$$ and $$\beta_0$$ denote compressibilities of solution and the solvent and $$n_i$$ and $$n_0$$ the amounts of solvate and solvent.

- Jytdog (talk) 00:32, 14 August 2016 (UTC)


 * The proof steps of this formula can be mentioned here (as mentioned in a Romanian language source which does not make further reference to other language sources). It remains that this formula be harmonized with the below mentioned formula from a Russian source that is also mentioned in another Romanian source where I've encountered without proof.--82.137.9.151 (talk) 18:58, 20 October 2016 (UTC)

First step: definitions

a) the hydration water as a fraction of the total amount of water

$$V_h = V_0 \frac{n_s n_i}{n_0}$$

b) the compressibility of pure water

$$ \beta_0 = -  \frac {1}{V_0} \left(\frac{\partial V_0}{\partial P} \right)_{T}$$

c) the compressiblity of the water in solution excluding the hydration shell water

$$ \beta = -  \frac {1}{V_0} \left(\frac{\partial (V_0- V_h)}{\partial P} \right)_{T}$$

d) final formula

$$\ n_s = (1 - \frac {\beta}{\beta_0}) \frac{n_i}{n_0}$$.--82.137.15.250 (talk) 20:25, 20 October 2016 (UTC)

Final steps: substitutions of Vh/(solvation number) from the first definition and the compressibility of the pure solvent/water from the second definition into the third relation and some rearrangements give the final formula.--82.137.14.98 (talk) 20:58, 20 October 2016 (UTC)

Several formulae harmonization
It seems that there are several derivations which need harmonization. A supplementary formula and derivation is to be found in a Russian language source which waits to be checked as discussed on User talk:R8R Gtrs.--82.137.10.242 (talk) 08:29, 6 October 2016 (UTC)

The following formula (from a Romanian source which points to a Russian source) about solvation shell the solvation number z (or ns), densities rho and compressibilities beta, molar masses of water and solution M, M0 and the mass concentration varrho of the dissolved ionic compound:
 * $$z = \frac{\rho - \rho_0 \frac{\beta}{\beta_0} - \varrho_1}{\varrho_1} \frac{M}{M_0}$$

needs to be harmonized with the first formula from above. The harmonization has to lead to a unique equation or to show the connection/interconversion between the two equalities.--82.137.15.79 (talk) 19:09, 20 October 2016 (UTC)

Sources list
A list of articles re solvation number of ions:

--185.53.198.232 (talk) 03:36, 17 November 2019 (UTC)
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