DMV
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Chlorine hydrate
I am wishing to make chlorine hydrate for use in precious metal digestions.
I have read that if chlorine gas is bubbled through a dilute calcium chloride solution (CaCl2) at about 0-6 °C it will be precipitated. I have also
read sodium chloride solutions as well as just water will work at those same temperatures.
Has anyone here done this and/or have any practical advice as to a preferred route?
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woelen
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I have tried it by making chlorine, leading the gas into a bottle with a little water in it and sealing the gas generator and the connected bottle
such that some pressure builds up. Then I quickly closed the bottle with the pure Cl2 and water in it and put this in a fridge (which was at 4 C). The
result was disappointing though. A lot of Cl2 dissolved in the water, but no crystals of chlorine hydrate were formed. Apparently making chlorine
hydrate is not that easy. Formation of chlorine hydrate is strongly favored by increased pressure, but my construct of bottles was not very good. At
most the pressure was 1.5 atmosphere or something close to that.
Besides that, chlorine hydrate is unstable and decomposes at temperatures above 10 C or so. I personally think that chlorine hydrate is not useful for
any practical purposes. It may be an interesting curiousity to play with, but practical applications are difficult due to its instability.
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DMV
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If you are right about its instability at 10C then you are correct, it would be of little use to me. I had read that it was stable at room
temperatures.
I am no chemist, but I would guess that the reason for the calcium chloride or sodium chloride solutions is to reduce the solubility of Cl2 in the
water. As you noted, water can hold a lot of Cl2. I do not plan on going this route even if stable if it will require several atmospheres.
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