Re: Van Dyck and Kallitype
Ryuji -- My point was mostly academic, I guess. One of the issues that seems to come up with Fe(III) oxalate is that it contains impurities that may interfere with kallitype/Pt-Pd printing. If the oxalate complex can be made "in situ" from a soluble iron(III) salt and an oxalate salt, reproducibilty might be improved. But again, I'm just hypothesizing.
The complex I use for actinometry has the formula K3 [Fe(C2O4)3] and is prepared from a titrated acid solution of Fe2(SO4)3 and excess K2C2O4. Oxalate is a good ligand for iron(III); I expect that iron(III) oxalate, Fe2(C2O4)3, is probably actually iron(III) ferrioxalate, Fe[Fe(C2O4)3].
Ryuji Suzuki wrote:
If your question is whether you can substitute Fe(III) oxalate with Fe(III) sulfate and alkali metal oxalate, I think the answer is positive, although I didn't test kallitype this way. Fe(III) oxalate is more stable than complex involving sulfate, and water should be the same as long as the pH is same... (but then you probably thought about it.) Sulfate is generally not reactive in silver chemistry. (Gelatin gets affected by it, though.) But was your point somewhere else?
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