I can't seem to find any information on forming the solid monohydrate from the solution form. The 50% solution was evaporated down to a very viscous
liquid which does not boil at 100C. This is no doubt the very hydroscopic Cesium Hydroxide with many water molecules still around it, so it looks
like some calcination is in order; however, I cannot find any references for what temperature to calcine it at to drive off all of the H2O's (with
exception of the mono); doing this would render it into a solid, rather than this syrupy, H2O rich liquid....can someone help?
[Edited on 26-2-2014 by zephler1]blogfast25 - 26-2-2014 at 05:26
That is going to absorb CO2 from the air like mad. I'm fairly sure you need vacuum to achieve what you are trying.nezza - 27-2-2014 at 06:47
What are you using as an evaporation vessel ?. My information is that CsOH dissolves glass so if it was in glass you may have some silicate there.
Dehydrating CsOH is going to be difficult.blogfast25 - 27-2-2014 at 13:20
My information is that CsOH dissolves glass [...].
I've heard this said countless times, yet have to see any solid evidence for it. Sure, hot, concentrated alkali metal hydroxides can etch glass to
some extent, that I've seen with hot 50 % NaOH on kitchenware pyrex glass (but far from putting the glass out of use).
Molten CsOH would be disastrous of course but that's a different matter. I have had an glass ampoule of solid CsOH for years and there's no sign of
corrosion of the glass whatsoever.
'dissolves' is a very strong term.Töilet Plünger - 27-2-2014 at 16:40
Cesium hydroxide is used to etch silicon wafers. Maybe the confusion arises with the differentiation between silicon and silicon dioxide.
Of course, silicon does passivate, so it must be able to eat through the layer.DJF90 - 27-2-2014 at 23:44
You'll need to concentrate your solution in a platinum dish. You may be able to use nickel instead as a cheaper alternative but I'd check that first
if I were you. I do have a reference somewhere for the concentration of aqueous solutions, though I'm not sure if it covers up to solid isolation.
I'll have a dig around when I've got time. You'll also want to use an inert atmosphere/vacuum as the carbonate is stable at relatively high temp.
I suppose the question you need to ask yourself is do you need to isolate the cesium hydroxide monohydrate or can you use the aqueous solution as it
is.
As for hydroxides vs glass... Think you'll find commercial suppliers use PP/PE containers for a reason. I'd be suspicious of a sample in glass, though
I can imagine if its a high purity sample it may be in an ampoule. If its from a reputable supplier its probably ok (though they make mistakes
sometimes, too).blogfast25 - 28-2-2014 at 01:31
