Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Sodium bicarbonate \Sodium bicarbonate\, a white crystalline substance, HNaCO3, with a slight alkaline taste resembling that of sodium carbonate. It is found in many mineral springs and also produced artificially,. It is used in cookery, in baking powders, and as a source of carbonic acid gas (carbon dioxide) for soda water. Called also baking soda, cooking soda, bicarbonate of soda, bicarb, saleratus, and technically, acid sodium carbonate, sodium acid carbonate, primary sodium carbonate, sodium dicarbonate, etc.
n. 1 (context chemistry English) A salt of sodium hydroxide and carbonic acid, NaHCO3. 2 This salt used in cooking as a raising agent, as an antacid, a cleaner, etc.
Sodium bicarbonate ( IUPAC name: sodium hydrogen carbonate) is a chemical compound with the formula Na HCO. It is a salt composed of sodium ions and bicarbonate ions. 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. It is a component of the mineral natron and is found dissolved in many mineral springs. It is among the food additives encoded by the European Union, identified as E 500. Since it has long been known and is widely used, the salt has many related names such as baking soda, bread soda, cooking soda, and bicarbonate of soda. In colloquial usage, the names sodium bicarbonate and bicarbonate of soda are often truncated. Forms such as sodium bicarb, bicarb soda, bicarbonate, bicarb, or even bica are common. The word saleratus, from Latinsal æratus meaning "aerated salt", was widely used in the 19th century for both sodium bicarbonate and potassium bicarbonate.
The prefix "bi" in "bicarbonate" comes from an outdated naming system and is based on the observation that there is twice as much carbonate (CO) per sodium in sodium bicarbonate (NaHCO) as there is carbonate per sodium in sodium carbonate (NaCO) and other carbonates. The modern way of analyzing the situation based on the exact chemical composition (which was unknown when the name "sodium bicarbonate" was coined) says this the other way around: there is half as much sodium in NaHCO as in NaCO (Na versus Na).