U of S | Mailing List Archive | alt-photo-process-l | Re: lithium bromide solubility ?

Re: lithium bromide solubility ?


yes, I think if you have information on a substantially larger solvability of LiI in EtOH than in water, you can assume te same for LiBr. If you use very small amounts of the LiBr, and start dissolving in small volums untill the concentration you want, and there is still complete solubility, the suaturation point is higher than the concentration you need. The method you propose will wok. If, during te experment, some crystals will not dissolve, even after warming in warm water for a bit (just a little over 20, say 30), ou can assume the wanted concentration probably needs other components in the solution.Good luck!


p.s. Did changig the fond work enough for you??

2008/9/9 Joseph Smigiel <jsmigiel@net-link.net>

Thanks for taking the time to look into this for me.

I have a solubility figure of 250.8 gm  LiI per 100 gm solvent at 25 degrees for ethyl alcohol from "Solubilities of Inorganic and Organic Compounds" by Atherton Seidell.  That source lists the solubility of LiI in water as 165 gm/100 gm water at 20 degrees which is in agreement with the information you've posted.  So, may I correctly assume the solubility of the lithium bromide will also be greater in ethanol than in water (and therefore in excess of 145 gm per 100 ml)?

I have 100 gm LiBr.  If I begin with some measured quantity of ethanol and in a separate graduate add it gradually to the entire quantity of salt until the salt is fully dissolved and then continue adding solvent until a standard volume is reached, would I then be able to calculate how many grams of LiBr are in each ml of the solution?  For example, if the salt dissolved fully in 150 ml ethanol and the resulting volume was 200 ml (or I brought it to that volume by adding more alcohol), then each ml of that solution would contain 0.5 gm salt.  Correct?  My aim is to achieve a simple way of calculating the amount of salt in a standard household volume of solution.

Thank you for your help.


ps. You can't spell Alt-Process List without Li.  :)

On Sep 8, 2008, at 6:48 AM, Dirk-Jan Treffers wrote:

Hi Joseph, Ryuji,
I've enclosed two pages from the book I've mentioned (Is this allowed by the list-rules? Otherwise, in the future, I'll send them to private emailadresses...).
If you chcek LiBr (page 4-69, first find Lithium in the first colum under name, then look for bromide, or look under synonyms and formulae in the second colum directly under LiBr), you'll see a solubility of 145 grams per 100 cc of cold water. On the second page, in the same way, you will find that LiI has a solubility of 165 grams per 100 cc of water. So, LiI dissolves better in water than LiBr. But both have excellent dissolving-characteristics. Under 'other solvents', last colum, you'll find no number, but both mention eth, short for ethanol/alcohol (usually the 95% form, most commonly..) so both dissolve in ethanol. I guess the solvability of LiI in ethanol will be better than LiBr in ethanol....
I can't find exact numbers for the solubility of these substances in ethanol, this is all I got. Hope it is good enough for you!

2008/9/8 Ryuji Suzuki <rs@silvergrain.org>
I understand your point, but I thought to add a common example where
the difference rather than the similarity is more enphasized. In case
of silver halide, there is about 1000-fold differences in the
solubilities of AgCl, AgBr, and AgI, in descending order, in
water. AgI is about a million times insoluble than AgCl. AgF is
soluble and very different from the other silver
halides. Incidentally, AgBr and AgI differ slightly in electric and
physical properties (including lattice distance) and this difference
is very effectively used in film emulsions to achive good grain to
speed ratio since about 1990.

From: Dirk-Jan Treffers <dirkjan.treffers@gmail.com>
Subject: Re: lithium bromide solubility ?
Date: Sun, 07 Sep 2008 18:20:54 +0200

> Usually, there is perhaps some difference between the chloro or fluoro-salts
> and the others, but between Br and I (bromium and iodine), I don't expect
> that many different physiscal or chemical properties!

<LiI and LiBr solubility.pdf>