Ferric ammonium oxalate
Ferric ammonium oxalate is the ammonium salt of the anionic trisoxalato coordination complex of iron. It is a precursor to iron oxides, diverse coordination polymers, and Prussian Blue. The latter behavior is relevant to the manufacture of blueprint paper. Ferric ammonium oxalate has also been used in the synthesis of superconducting salts with bisdithiotetrathiafulvalene, see Organic superconductor.