Sodium bicarbonate
Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula Na
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

In inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...

. Sodium bicarbonate is a white solid that is crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

line but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate
Sodium carbonate
Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...

). The natural mineral form is nahcolite
Nahcolite is a soft, colourless or white carbonate mineral with the composition of sodium bicarbonate also called thermokalite. It crystallizes in the monoclinic system....

. It is a component of the mineral natron
Natron is a naturally occurring mixture of sodium carbonate decahydrate and about 17% sodium bicarbonate along with small quantities of household salt and sodium sulfate. Natron is white to colourless when pure, varying to gray or yellow with impurities...

 and is found dissolved in many mineral spring
Mineral spring
Mineral springs are naturally occurring springs that produce water containing minerals, or other dissolved substances, that alter its taste or give it a purported therapeutic value...

s. It is found in dissolved form in bile
Bile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the process of digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and upon eating is discharged into the duodenum...

, where it serves to neutralize the acidity of the hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

 produced by the stomach, and is excreted into the duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...

 of the small intestine via the bile duct.