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Glauber's salt

Sodium sulfate
Sodium sulfate.jpg
Sodium sulfate.png
Names
Other names
Thenardite (mineral)
Glauber's salt (decahydrate)
Sal mirabilis (decahydrate)
Mirabilite (decahydrate)
Disodium sulfate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.028.928
E number E514 (acidity regulators, ...)
PubChem CID
RTECS number WE1650000
UNII
Properties
Na2SO4
Molar mass 142.04 g/mol (anhydrous)
322.20 g/mol (decahydrate)
Appearance white crystalline solid
hygroscopic
Odor odorless
Density 2.664 g/cm3 (anhydrous)
1.464 g/cm3 (decahydrate)
Melting point 884 °C (1,623 °F; 1,157 K) (anhydrous)
32.38 °C (decahydrate)
Boiling point 1,429 °C (2,604 °F; 1,702 K) (anhydrous)
anhydrous:
4.76 g/100 mL (0 °C)
13.9 g/100 mL (20 °C)
42.7 g/100 mL (100 °C)
heptahydrate:
19.5 g/100 mL (0 °C)
44 g/100 mL (20 °C)
Solubility insoluble in ethanol
soluble in glycerol, water and hydrogen iodide
−52.0·10−6 cm3/mol
1.468 (anhydrous)
1.394 (decahydrate)
Structure
orthorhombic or hexagonal (anhydrous)
monoclinic (decahydrate)
Pharmacology
A06AD13 (WHO) A12CA02 (WHO)
Hazards
Main hazards Irritant
Safety data sheet See: data page
ICSC 0952
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine 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
Flash point Non-flammable
Related compounds
Other anions
Sodium selenate
Sodium tellurate
Other cations
Lithium sulfate
Potassium sulfate
Rubidium sulfate
Caesium sulfate
Related compounds
Sodium bisulfate
Sodium sulfite
Sodium persulfate
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Sodium sulfate, also known as sulfate of soda, is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 million tonnes, the decahydrate is a major commodity chemical product. It is mainly used for the manufacture of detergents and in the kraft process of paper pulping.

The decahydrate of sodium sulfate is known as Glauber's salt after the Dutch/German chemist and apothecary Johann Rudolf Glauber (1604–1670), who discovered it in 1625 in Austrian spring water. He named it sal mirabilis (miraculous salt), because of its medicinal properties: the crystals were used as a general purpose laxative, until more sophisticated alternatives came about in the 1900s.

In the 18th century, Glauber's salt began to be used as a raw material for the industrial production of soda ash (sodium carbonate), by reaction with potash (potassium carbonate). Demand for soda ash increased and the supply of sodium sulfate had to increase in line. Therefore, in the nineteenth century, the large scale Leblanc process, producing synthetic sodium sulfate as a key intermediate, became the principal method of soda ash production.

Sodium sulfate is very stable, being unreactive toward most oxidizing or reducing agents at normal temperatures. At high temperatures, it can be converted to sodium sulfide by carbothermal reduction:

Sodium sulfate is a neutral salt: its aqueous solutions exhibit a pH of 7. The neutrality of such solutions reflects the fact that sulfate is derived, formally, from the strong acid sulfuric acid. Furthermore, the Na+ ion, with only a single positive charge, only weakly polarizes its water ligands provided there are metal ions in solution. Sodium sulfate reacts with sulfuric acid to give the acid salt sodium bisulfate:


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