[alt-photo] Re: "Moistened" AD (4th and final attempt)

[Tomas Sobota]

Well, it could be that removing the last 0.5% - 3% of water is difficult or
expensive, or that the anhydrous product is difficult to keep, but I don't
really know. I think that the crystallised form also has a certain amount of
structural water.
For alt photo purposes there would be no difference since you will be mixing
it with water anyway.
A couple of years ago I paid some 20 euros for a kg of the product
(technical grade) here in Madrid, so you see that there is a difference
between technical and reagent grade.
Tom Sobota
Madrid, Spain

On Thu, Jan 7, 2010 at 7:46 PM, Trevor Cunningham
<trevor at chalkjockeys.com>wrote:

> 1kg of the powder is a little over $100. But the moistened is actually a
> little cheaper. As long as it does the same thing, I'm a happy camper. I get
> the impression from them that they might need to back order the crystal
> form. Would storage become an issue with keeping it "moist"? Or could I turn
> it all into solution and leave it on the shelf?
>
> What does .5% - 3 water mean? The sheet you linked is exactly the same
> product, # and all.
>
>
>
> Tomas Sobota wrote:
>
>> Not sure why they moist the Am. dichromate (0.5% - 3 water) but this is a
>> pure reagent for analysis and it will probably be expensive.
>>
>
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