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 (Jmol)

CHEBI:32149^Y

ChEMBL233406^Y

22844^Y

E514 (acidity regulators, ...)

WE1650000

36KCS0R750^Y

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 (n_D)

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

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 (ε_r), 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).

(what is ^YN ?)

Infobox references

Sodium sulfate 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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