Potassium bicarbonate dry chemical fire extinguishers, as the principal component of the Purple-K dry chemical, and in some applications of condensed aerosol fire suppression. It is the only dry chemical fire suppression agent recognized by the U.S. National Fire Protection Association for firefighting at airport crash rescue sites. It is about twice as effective in fire suppression as sodium bicarbonate. Potassium bicarbonate is an effective fungicide against powdery mildew and apple scab, allowed for use in organic farming. Potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil. The word "saleratus", from Latin "sal æratus" meaning "aerated salt", was widely
Potassium pyrosulfate Potassium pyrosulfate Potassium pyrosulfate, or potassium disulfate, is an inorganic compound with the chemical formula KSO. Potassium pyrosulfate is obtained by the thermal decomposition of other salts, most directly from potassium bisulfate: Temperatures above 600°C further decompose potassium pyrosulfate to potassium sulfate and sulfur trioxide however: Other salts, such as potassium trisulfate, can also decompose into potassium pyrosulfate. Potassium pyrosulfate contains the pyrosulfate anion which has a dichromate like structure. The geometry can be visualized as a tetrahedron with two corners sharing the SO anion's configuration and a centrally bridged oxygen atom. A semi-structural formula for the pyrosulfate anion is