Sodium carbonate

Sodium carbonate
Skeletal formula of sodium carbonate
Space-filling model of sodium carbonate
Sample of sodium carbonate
IUPAC name
Sodium carbonate
Other names
Soda ash, Washing soda, Soda crystals
3D model ( JSmol)
ECHA InfoCard 100.007.127
EC Number 207-838-8
E number E500 (acidity regulators, ...)
PubChem CID
RTECS number VZ4050000
Molar mass 105.9888 g/mol (anhydrous)
286.1416 g/mol (decahydrate)
Appearance White solid, hygroscopic
Odor Odorless
Density 2.54 g/cm3 (25 °C, anhydrous)
1.92 g/cm3 (856 °C)
2.25 g/cm3 (monohydrate) [1]
1.51 g/cm3 (heptahydrate)
1.46 g/cm3 (decahydrate) [2]
Melting point 851 °C (1,564 °F; 1,124 K)
decomposes (anhydrous)
100 °C (212 °F; 373 K)
decomposes (monohydrate)
33.5 °C (92.3 °F; 306.6 K)
decomposes (heptahydrate)
34 °C (93 °F; 307 K)
(decahydrate) [2] [6]
7 g/100 mL (0 °C)
16.4 g/100 mL (15 °C)
34.07 g/100 mL (27.8 °C)
48.69 g/100 mL (34.8 °C)
50.31 g/100 mL (29.9 °C)
48.1 g/100 mL (41.9 °C)
45.62 g/100 mL (60 °C)
43.6 g/100 mL (100 °C) [3]
Solubility Soluble in aq. alkalis, [3] glycerol
Slightly soluble in aq. alcohol
Insoluble in CS2, acetone, alkyl acetates, alcohol, benzonitrile, liquid ammonia [4]
Solubility in glycerine 98.3 g/100 g (15.5 °C) [4]
Solubility in ethanediol 3.46 g/100 g (20 °C) [5]
Solubility in dimethylformamide 0.5 g/kg [5]
Basicity (pKb) 3.67
−4.1·10−5 cm3/mol [2]
1.485 (anhydrous)
1.420 (monohydrate) [6]
1.405 (decahydrate)
Viscosity 3.4 cP (887 °C) [5]
Monoclinic (γ-form, β-form, δ-form, anhydrous) [7]
Orthorhombic (monohydrate, heptahydrate) [1] [8]
C2/m, No. 12 (γ-form, anhydrous, 170 K)
C2/m, No. 12 (β-form, anhydrous, 628 K)
P21/n, No. 14 (δ-form, anhydrous, 110 K) [7]
Pca21, No. 29 (monohydrate) [1]
Pbca, No. 61 (heptahydrate) [8]
2/m (γ-form, β-form, δ-form, anhydrous) [7]
mm2 (monohydrate) [1]
2/m 2/m 2/m (heptahydrate) [8]
a = 8.920(7) Å, b = 5.245(5) Å, c = 6.050(5) Å (γ-form, anhydrous, 295 K) [7]
α = 90°, β = 101.35(8)°, γ = 90°
Octahedral (Na+, anhydrous)
112.3 J/mol·K [2]
135 J/mol·K [2]
−1130.7 kJ/mol [2] [5]
−1044.4 kJ/mol [2]
Safety data sheet MSDS
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) [9]
GHS signal word Warning
H319 [9]
P305+351+338 [9]
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
LD50 ( median dose)
4090 mg/kg (rat, oral) [10]
Related compounds
Other anions
Sodium bicarbonate
Other cations
Lithium carbonate
Potassium carbonate
Rubidium carbonate
Caesium carbonate
Related compounds
Sodium sesquicarbonate
Sodium percarbonate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify ( what is YesYN ?)
Infobox references

Sodium carbonate (also known as washing soda, soda ash and soda crystals, and in the monohydrate form as crystal carbonate), Na2CO3, is the water-soluble sodium salt of carbonic acid.

It most commonly occurs as a crystalline decahydrate, which readily effloresces to form a white powder, the monohydrate. Pure sodium carbonate is a white, odorless powder that is hygroscopic (absorbs moisture from the air). It has a strongly alkaline taste, and forms a moderately basic solution in water. Sodium carbonate is well known domestically for its everyday use as a water softener. Historically it was extracted from the ashes of plants growing in sodium-rich soils, such as vegetation from the Middle East, kelp from Scotland and seaweed from Spain. Because the ashes of these sodium-rich plants were noticeably different from ashes of timber (used to create potash), they became known as "soda ash". [12] It is synthetically produced in large quantities from salt ( sodium chloride) and limestone by a method known as the Solvay process.

The manufacture of glass is one of the most important uses of sodium carbonate. Sodium carbonate acts as a flux for silica, lowering the melting point of the mixture to something achievable without special materials. This "soda glass" is mildly water-soluble, so some calcium carbonate is added to the melt mixture to make the glass produced insoluble. This type of glass is known as soda lime glass: "soda" for the sodium carbonate and "lime" for the calcium carbonate. Soda lime glass has been the most common form of glass for centuries.

Sodium carbonate is also used as a relatively strong base in various settings. For example, it is used as a pH regulator to maintain stable alkaline conditions necessary for the action of the majority of photographic film developing agents. It acts as an alkali because when dissolved in water, it dissociates into the weak acid: carbonic acid and the strong alkali: sodium hydroxide. This gives sodium carbonate in solution the ability to attack metals such as aluminium with the release of hydrogen gas. [13]

It is a common additive in swimming pools used to raise the pH which can be lowered by chlorine tablets and other additives which contains acids.

In cooking, it is sometimes used in place of sodium hydroxide for lyeing, especially with German pretzels and lye rolls. These dishes are treated with a solution of an alkaline substance to change the pH of the surface of the food and improve browning.

In taxidermy, sodium carbonate added to boiling water will remove flesh from the skull or bones of trophies to create the "European skull mount" or for educational display in biological and historical studies.

In chemistry, it is often used as an electrolyte. Electrolytes are usually salt-based, and sodium carbonate acts as a very good conductor in the process of electrolysis. In addition, unlike chloride ions, which form chlorine gas, carbonate ions are not corrosive to the anodes. It is also used as a primary standard for acid-base titrations because it is solid and air-stable, making it easy to weigh accurately.

Domestic use

Soda ash is used as a water softener in laundering: it competes with the magnesium and calcium ions in hard water and prevents them from bonding with the detergent being used, but doesn't prevent scaling. [14] Sodium carbonate can be used to remove grease, oil, and wine stains.

In dyeing with fiber-reactive dyes, sodium carbonate (often under a name such as soda ash fixative or soda ash activator) is used to ensure proper chemical bonding of the dye with cellulose (plant) fibers, typically before dyeing (for tie dyes), mixed with the dye (for dye painting), or after dyeing (for immersion dyeing).

Other Languages
Bân-lâm-gú: Thoàⁿ-sng natrium
bosanski: Natrij-karbonat
dansk: Soda
Esperanto: Natria karbonato
客家語/Hak-kâ-ngî: Thàn-sôn-na̍p
한국어: 탄산 나트륨
Bahasa Indonesia: Natrium karbonat
Nederlands: Natriumcarbonaat
norsk nynorsk: Natriumkarbonat
oʻzbekcha/ўзбекча: Natriy karbonat
polski: Węglan sodu
Simple English: Sodium carbonate
slovenčina: Uhličitan sodný
slovenščina: Natrijev karbonat
српски / srpski: Natrijum karbonat
srpskohrvatski / српскохрватски: Natrijum karbonat
suomi: Sooda
Türkçe: Sodyum karbonat
українська: Карбонат натрію
Tiếng Việt: Natri cacbonat
粵語: 鹼粉
中文: 碳酸钠