Sodium bicarbonate

Not to be confused with Sodium carbonate.
For the leavening agent of which baking soda is a common ingredient, see Baking powder.

Sodium bicarbonate
Ball and stick model of a sodium cation
Ball and stick model of a sodium cation
Ball and stick model of a bicarbonate anion
Ball and stick model of a bicarbonate anion
HCO3− coordination
Names
IUPAC name
sodium hydrogencarbonate
Other names
Baking soda, bicarb (laboratory slang), bicarbonate of soda, nahcolite, natrium hydrogen carbonate, natron
Identifiers
3D model (JSmol)
4153970
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.005.122 Edit this at Wikidata
EC Number
  • 205-633-8
E number E500(ii) (acidity regulators, ...)
KEGG
MeSH Sodium+bicarbonate
RTECS number
  • VZ0950000
UNII
  • InChI=1S/CH2O3.Na/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 checkY
    Key: UIIMBOGNXHQVGW-UHFFFAOYSA-M checkY
  • InChI=1/CH2O3.Na/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1
    Key: UIIMBOGNXHQVGW-REWHXWOFAQ
  • [Na+].OC([O-])=O
Properties
NaHCO
3
Molar mass 84.0066 g mol−1
Appearance White crystals
Odor Odorless
Density
Melting point (Decomposes to sodium carbonate starting at 50 °C[1][6])
Solubility 0.02 wt% acetone, 2.13 wt% methanol @22 °C.[4] insoluble in ethanol
log P −0.82
Acidity (pKa)
  • 6.34[5]
  • 6.351 (carbonic acid)[5]
nα = 1.377 nβ = 1.501 nγ = 1.583
Structure
Monoclinic
Thermochemistry
87.6 J/mol K[7]
101.7 J/mol K[7]
−950.8 kJ/mol[7]
−851.0 kJ/mol[7]
Pharmacology
B05CB04 (WHO) B05XA02 (WHO), QG04BQ01 (WHO)
Intravenous, oral
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Causes serious eye irritation
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
2
0
1
Flash point Incombustible
Lethal dose or concentration (LD, LC):
4220 mg/kg (rat, oral)[8]
Safety data sheet (SDS) External MSDS
Related compounds
Other anions
 Sodium carbonate
Other cations
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Cupcakes baked with baking soda as a raising agent

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).

  1. ^ a b Haynes, p. 4.90
  2. ^ a b c Haynes, p. 5.194
  3. ^ a b c "Sodium Bicarbonate" (PDF). United Nations Environment Programme. Archived from the original (PDF) on 16 May 2011.
  4. ^ Ellingboe JL, Runnels JH (1966). "Solubilities of Sodium Carbonate and Sodium Bicarbonate in Acetone-Water and Methanol-Water Mixtures". J. Chem. Eng. Data. 11 (3): 323–324. doi:10.1021/je60030a009.
  5. ^ a b Haynes, p. 7.23
  6. ^ Pasquali I, Bettini R, Giordano F (2007). "Thermal behaviour of diclofenac, diclofenac sodium and sodium bicarbonate compositions". Journal of Thermal Analysis and Calorimetry. 90 (3): 903–907. doi:10.1007/s10973-006-8182-1. S2CID 95695262.
  7. ^ a b c d Haynes, p. 5.19
  8. ^ Griffith JF (1964). "Interlaboratory variations in the determination of acute oral LD50". Toxicology and Applied Pharmacology. 6 (6): 726–730. doi:10.1016/0041-008X(64)90124-3. PMID 14235840.
  9. ^ Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005 (PDF), IUPAC, p. 137, archived (PDF) from the original on 18 May 2017
  10. ^ Gärtner RS, Witkamp GJ (August 2007). "Mixed solvent reactive recrystallization of trona (sodium sesqui-carbonate) into soda (sodium carbonate anhydrate)". Hydrometallurgy. 88 (1–4): 75–91. Bibcode:2007HydMe..88...75G. doi:10.1016/j.hydromet.2007.03.006.
  11. ^ "Baking powder, baking soda or bicarbonate of soda?". Reader's Digest Australia. Retrieved 2 June 2024.
  12. ^ PubChem. "Sodium bicarbonate". pubchem.ncbi.nlm.nih.gov. Retrieved 25 January 2021.
  13. ^ Wollaston WH (January 1814). "I. A Synoptic scale of chemical equivalents". Philosophical Transactions of the Royal Society of London. 104: 1–22. doi:10.1098/rstl.1814.0001. S2CID 96774986.