Potassium ferrooxalate


Potassium ferrooxalate, also known as potassium bisoxalatoferrate, is a salt with the formula. The anion is a transition metal oxalate complex, consisting of an atom of iron in the +2 oxidation state bound to oxalate ligands and water.
Anhydrous has been prepared by hydrothermal methods from ferrous chloride. It is a coordination polymer with trigonal prismatic centers. Half of the oxalate ligands are bridging.

Dihydrate

The material has been claimed but not verified. Potassium ferrooxalate is believed to be formed when the related compound potassium ferrioxalate is decomposed by light in solution or heated above. The anhydrous salt is orange-yellow and dissolves in water to give a red solution. Crystals of the dihydrate are golden yellow in color.