Potassium ferrocyanide, also known as potassium hexacyanoferrate(II), is a chemical compound commonly used in various industrial and laboratory applications. It is a yellow crystalline powder that is soluble in water and forms a complex ion when exposed to oxidizing agents. Other synonyms for potassium ferrocyanide include yellow prussiate of potash, potassium hexacyanoferrate, and Berlin green. It is used in the production of pigments, for example, Prussian blue and Turnbull's blue. It also has applications in photography, electroplating, and as a food additive in the form of E536. Despite its many uses, potassium ferrocyanide can be a toxic substance and should be handled with care when in use.