Tetrapotassium ferrocyanide
Potassium ferrocyanide is a coordination compound of potassium, iron, and cyanide. It is used in gardening as a nitrogen supplement and in industry for metal extraction and the production of adhesives, computer electronics, fire retardants, cosmetics, dyes, nylon, paints, inks, plexiglass, pharmaceuticals, and rocket propellant. (L560)