Barium ferrate is the most stable of the ferrate compounds. The reaction for the formation of barium ferrate is vigorous and very strong chlorine odor. There are two methods for producing ferrate (VI)&colon; dry and wet synthetic methods. Barium ferrate is the chemical compound of formula BaFeO. The byproduct of ferrate oxidation is the relatively benign iron(III), or ferric oxide. Potassium ferrate is the chemical compound with the formula KFeO. Thoroughly dried barium ferrate is decomposed completely by hydrochloric acid, releasing chlorine. Barium ferrate can be purified by washing with petroleum spirit. The anion is typically precipitated as the barium(II) salt, forming barium ferrate. The term ferrate derives from the Latin word for iron, "ferrum". Barium ferrate, therefore, appears to be one of the most insoluble salts known. Ferrate is a tetrahedral ion isostructural with the chromate and permanganate ions. Ferrate loosely refers to a material that can be viewed as containing anionic iron complexes. Ferrate is one of the most powerful, yet environmentally friendly, water treatment chemicals known.