[Alt-photo] Cyanotype chemistry question

Chris Seiberling christopher.seiberling at gmail.com
Sat Jan 25 20:55:19 UTC 2020


Thanks! I see that both have the same CAS Number. It’s curious to me that it’s possible to buy both of them even if they’re the same, chemically.

Chris Seiberling, Sharon MA

> On Jan 25, 2020, at 2:18 PM, Kelcy Patterson <jimbobnola at cox.net> wrote:
> 
> Hi, the first formula is grouped by ions: NH4 = ammonium ion, Fe = ferric (iron III) ion, C2O4 = oxalate ion, with .3H2O being 3 waters of hydration.
> 
> The second formula is grouped by total elements. It is the same, minus the 3 waters of hydration.
> 
> Jim Patterson, New Orleans
>> On January 25, 2020 at 11:27 AM Chris Seiberling via Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org <mailto:alt-photo-process-list at lists.altphotolist.org>> wrote:
>> 
>> 
>> Hello photographic chemists (and others):
>> 
>> Mike Ware's 'New' Cyanotype calls for Ammonium iron(III) oxalate-- (NH4)3[Fe(C2O4)3].3H2O. He says this is also known as ferric ammonium oxalate. But I understand ferric ammonium oxalate's formula to be C6H12FeN3O12 ? Is there a practical difference? I’m not enough of a chemist to understand the formulaic implications. 
>> 
>> Thanks, Chris Seiberling
>> 
>> 
>> 
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