Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate[9]), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation (Na+) and a bicarbonate anion (HCO3−). Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is nahcolite, although it is more commonly found as a component of the mineral trona.[10] As it has long been known and widely used, the salt has many different names such as baking soda, bread soda, cooking soda, brewing soda and bicarbonate of soda and can often be found near baking powder in stores. The term baking soda is more common in the United States, while bicarbonate of soda is more common in Australia, the United Kingdom, and New Zealand.[11] Abbreviated colloquial forms such as sodium bicarb, bicarb soda, bicarbonate, and bicarb are common.[12] The prefix bi- in "bicarbonate" comes from an outdated naming system predating molecular knowledge. It is based on the observation that there is twice as much carbonate (CO3−2) per sodium in sodium bicarbonate (NaHCO3) as there is in sodium carbonate (Na2CO3).[13] The modern chemical formulas of these compounds now express their precise chemical compositions which were unknown when the name bi-carbonate of potash was coined (see also: bicarbonate). Uses Cooking Main article: Leavening agent Wikibooks Cookbook has a recipe/module on Baking Soda In cooking, baking soda is primarily used in baking as a leavening agent. When it reacts with acid or is heated, carbon dioxide is released, which causes expansion of the batter and forms the characteristic texture and grain in cakes, quick breads, soda bread, and other baked and fried foods. When an acid is used, the acid–base reaction can be generically represented as follows:[14] NaHCO3 + H+ → Na+ + CO2 + H2O Acidic materials that induce this reaction include hydrogen phosphates, cream of tartar, lemon juice, yogurt, buttermilk, cocoa, and vinegar. Baking soda may be used together with sourdough, which is acidic, making a lighter product with a less acidic taste.[15] Since the reaction occurs slowly at room temperature, mixtures (cake batter, etc.) can be allowed to stand without rising until they are heated in the oven.[citation needed] Heat can also by itself cause sodium bicarbonate to act as a raising agent in baking because of thermal decomposition, releasing carbon dioxide at temperatures above 80 °C (180 °F), as follows:[16] 2 NaHCO3 → Na2CO3 + H2O + CO2 When used this way on its own, without the presence of an acidic component (whether in the batter or by the use of a baking powder containing acid), only half the available CO2 is released (one CO2 molecule is formed for every two equivalents of NaHCO3). Additionally, in the absence of acid, thermal decomposition of sodium bicarbonate also produces sodium carbonate, which is strongly alkaline and gives the baked product a bitter, soapy taste and a yellow color.