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Citric acid
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<p>Citric acid is an <a href="/facts/Organic_compound/gqCNaN45">organic compound</a> with the formula C6H8O7. It is a <a href="/facts/Transparency_and_translucency/PRryNNW6">colorless</a> <a href="/facts/Weak_acid/vJ4rj6Lu">weak</a> <a href="/facts/Organic_acid/2Pfb26Lp">organic acid</a>. It occurs naturally in <a href="/facts/Citrus/6FqG38Dk">citrus fruits</a>. In <a href="/facts/Biochemistry/fa2pWEBp">biochemistry</a>, it is an intermediate in the <a href="/facts/Citric_acid_cycle/EGJL9NXP">citric acid cycle</a>, which occurs in the <a href="/facts/Metabolism/WxDrm8k5">metabolism</a> of all <a href="/facts/Aerobic_organism/a629EQD7">aerobic organisms</a>. </p><p>More than two million tons of citric acid <a href="/facts/Commodity_chemicals/qnKIcKIx">are manufactured</a> every year. It is used widely as <a href="/facts/Acidifier/nAs3eVlX">acidifier</a>, <a href="/facts/Flavoring/sGR38zXy">flavoring</a>, <a href="/facts/Preservative/sm1IDmDT">preservative</a>, and <a href="/facts/Chelating_agent/4G79sXBB">chelating agent</a>. </p><p>A citrate is a derivative of citric acid; that is, the <a href="/facts/Salt_(chemistry)/lsSKwGpn">salts</a>, <a href="/facts/Ester/FoUAIIw4">esters</a>, and the <a href="/facts/Polyatomic_ion/FcPWAyLm">polyatomic anion</a> found in solutions and salts of citric acid. An example of the former, a salt is <a href="/facts/Trisodium_citrate/nINV5Cmu">trisodium citrate</a>; an ester is <a href="/facts/Triethyl_citrate/9eCEArS6">triethyl citrate</a>. When citrate <a href="/facts/Anion/wrbwhF3z">trianion</a> is part of a salt, the formula of the citrate trianion is written as C6H5O3−7 or C3H5O(COO)3−3. </p>