Ammonium sulfate

Ammonium sulfate
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IUPAC name	Ammonium sulfate
Other names	ammonium sulfate (2:1); diammonium sulfate; sulfuric acid diammonium salt; mascagnite; Actamaster; Dolamin
Identifiers
CAS number	7783-20-2
SMILES	[O-]S([O-])(=O)=O.[NH4+].[NH4+]
Properties
Molecular formula	(NH4)2SO4
Molar mass	132.14 g/mol
Appearance	Fine white hygroscopic granules or crystals.
Density	1.77 g/cm³ @ 50 °C (122 °F)
Melting point	235-280 °C, 508-553 K, 455-536 °F (decomposes)
Solubility in water	70.6 g/100 mL (0 °C) and 103.8 g/100 mL (100 °C)
Critical relative humidity	79.2% at 30 °C
Related Compounds
Related compounds	Ammonium iron sulfate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Ammonium sulfate, ((NH₄)₂SO₄), is an inorganic chemical compound commonly used as a fertilizer. It contains 21% nitrogen as ammonium ions and 24% sulfur as sulfate ions.

Properties

Ammonium sulfate is not soluble in alcohol or liquid ammonia. The compound is slightly hygroscopic and absorbs water from the air at relative humidity > 81% (at ca. 20°C).

Synthesis

Ammonium sulfate is prepared commercially by reacting ammonia with sulfuric acid (H₂SO₄). Ammonium sulfate is prepared commercially from the ammoniacal liquor of gas-works and is purified by recrystallisation. It forms large rhombic prisms, has a somewhat saline taste and is easily soluble in water. The aqueous solution on boiling loses some ammonia and forms an acid sulfate.

Uses

It is used largely as an artificial fertilizer for alkaline soils. In the soil the sulfate ion is released and forms sulfuric acid, lowering the pH balance of the soil (as do other sulfate compounds such as aluminium sulfate), while contributing essential nitrogen for plant growth.

It is also used as an agricultural spray adjuvant for water soluble insecticides, herbicides, and fungicides. There it functions to bind iron and calcium cations that are present in both well water and plant cells. It is particularly effective as an adjuvant for 2,4-D (amine), glyphosate, and glufosinate herbicides.

It is also used in the preparation of other ammonium salts.

In biochemistry ammonium sulfate precipitation is a common method for purifying proteins.

Ammonium sulfate is also listed as an ingredient for many United States vaccines per the Center for Disease Control.

Ammonium sulfate is also a food additive.

Further reading

• Properties: UNIDO and International Fertilizer Development Center (1998), Fertilizer Manual, Kluwer Academic Publishers, ISBN 0-7923-5032-4.ar:كبريتات أمونيوم