Glauber's salt

Sodium sulfate

Names
Other names Thenardite (mineral) Glauber's salt (decahydrate) Sal mirabilis (decahydrate) Mirabilite (decahydrate) Disodium sulfate
Identifiers
CAS Number	7757-82-6 Y 7727-73-3 (decahydrate) N
3D model (JSmol)	Interactive image
ChEBI	CHEBI:32149 Y
ChemSpider	22844 Y
ECHA InfoCard	100.028.928
E number	E514 (acidity regulators, ...)
PubChem CID	24436
RTECS number	WE1650000
UNII	36KCS0R750 Y
InChI InChI=1S/2Na.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Y Key: PMZURENOXWZQFD-UHFFFAOYSA-L Y InChI=1S/2Na.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 InChI=1S/2Na.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Key: PMZURENOXWZQFD-UHFFFAOYSA-L
SMILES [Na+].[Na+].[O-]S([O-])(=O)=O
Properties
Chemical formula	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)
Solubility in water	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
Magnetic susceptibility (χ)	−52.0·10−6 cm3/mol
Refractive index (nD)	1.468 (anhydrous) 1.394 (decahydrate)
Structure
Crystal structure	orthorhombic or hexagonal (anhydrous) monoclinic (decahydrate)
Pharmacology
ATC code	A06AD13 (WHO) A12CA02 (WHO)
Hazards
Main hazards	Irritant
Safety data sheet	See: data page ICSC 0952
NFPA 704	0 1 0
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
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	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 YN ?)
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: