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
Period 6 element niobium, occurs in the minerals tantalite, columbite and coltan (a mix of columbite and tantalite). Tungsten, also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74. The word "tungsten" comes from the Swedish language "tung sten" directly translatable to "heavy stone", though the name is "volfram" in Swedish to distinguish it from Scheelite, in Swedish alternatively named "tungsten". A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in