It will be I think Iron-III-oxalate. Fe2(C2O4)3
That is a real compound
. But I wonder whether one can get the "biolxalate" too.
Compare sodium carbonate Na2
with sodium bicarbonate NaHCO3
. Both are stable in normal conditions, but heating the latter yields the former with release of water:
The only bicarbonates that are stable as solids at normal conditions are basically the alkali and ammonium ones. However, oxalic acid is stable while carbonic acid is unstable. So perhaps bi-oxalates (hydrogen oxalates) of other cations, like iron(III) are stable too.
Calcium bicarbonate does exists in solution; rather, one can have a solution with Ca2+
. Likewise, in a solution that is acid enough (pH 2.5 - 3) one can have Fe3+
with little oxalate. The question is whether one can evaporate that solution without losing the hydrogen-oxalate.