[alt-photo] Re: "Expired" dichromate

[Judy Seigel]

On Thu, 29 Apr 2010, Trevor Cunningham wrote:

> I just got back from the chemical supplier and hey informed me that the only 
> ammonium dichromate they stock is a moistened product that has expired...in 
> 2005. I'm not sure what they mean by expired, and the supplier want to know 
> if I still want it. Any thoughts?

I've used ammonium dichromate mixed some 4 or 5 years earlier to working 
strength, then stored in a brown glass bottle, and found it performed as 
usual. Since, as I understand it, the more a chemical is diluted the less 
well it keeps, that suggests that the supplier's relatively concentrated 
stock would be fine. (Presumably, however, they'd let you get a relatively 
small amount, at a good price to try...)

J.