Potassium ferrate (K₂FeO₄) is an inorganic compound with the CAS number 39469-86-8. It is a dark purple crystalline solid containing iron in the +6 oxidation state. It is known for its strong oxidizing properties and is relatively unstable, decomposing in water or moist air to release oxygen and form ferric hydroxide. Its primary and most significant application is in advanced water and wastewater treatment. It functions as a potent disinfectant, effectively inactivating a broad spectrum of pathogens including bacteria and viruses. Simultaneously, it acts as a coagulant and flocculant, removing heavy metals, organic contaminants, and phosphates by oxidation and subsequent precipitation. This dual action makes it a promising "green" chemical for treating drinking water, industrial effluent, and for sludge conditioning. Beyond water treatment, potassium ferrate is investigated as a "super-iron" cathode material in electrochemical cells due to its high charge capacity. In synthetic chemistry, it serves as a selective and environmentally benign oxidizing reagent for organic transformations, such as the oxidation of alcohols and sulfides, offering the advantage of producing non-toxic byproducts (iron(III) oxide/hydroxide).