Potassium sulfate

Last updated
Potassium sulfate
Arcanite.jpg
Arcanite
Potassium-sulfate-chemical.png
Names
Other names
Potassium sulphate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.029.013 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 231-915-5
E number E515(i) (acidity regulators, ...)
KEGG
PubChem CID
RTECS number
  • TT5900000
UNII
  • InChI=1S/2K.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Yes check.svgY
    Key: OTYBMLCTZGSZBG-UHFFFAOYSA-L Yes check.svgY
  • InChI=1/2K.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2
    Key: OTYBMLCTZGSZBG-NUQVWONBAU
  • [K+].[K+].[O-]S([O-])(=O)=O
Properties
K2SO4
Molar mass 174.259 g/mol
AppearanceWhite solid
Odor odorless
Density 2.66 g/cm3 [1]
Melting point 1,069 [2]  °C (1,956 °F; 1,342 K)
Boiling point 1,689 °C (3,072 °F; 1,962 K)
111 g/L (20 °C)
120 g/L (25 °C)
240 g/L (100 °C)
1.32 (120 g/L)
Solubility slightly soluble in glycerol
insoluble in acetone, alcohol, CS2
−67.0·10−6 cm3/mol
1.495
Structure
orthorhombic
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Irritant
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H318
P280, P305+P351+P338, P310
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
6600 mg/kg (oral, rat) [3]
Safety data sheet (SDS) External MSDS
Related compounds
Other anions
Potassium selenate
Potassium tellurate
Other cations
Lithium sulfate
Sodium sulfate
Rubidium sulfate
Caesium sulfate
Related compounds
 Potassium hydrogen sulfate
Potassium sulfite
Potassium bisulfite
Potassium persulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Potassium sulfate (US) or potassium sulphate (UK), also called sulphate of potash (SOP), arcanite, or archaically potash of sulfur, is the inorganic compound with formula K2SO4, a white water-soluble solid. It is commonly used in fertilizers, providing both potassium and sulfur.

Contents

History

Potassium sulfate (K2SO4) has been known since early in the 14th century. It was studied by Glauber, Boyle, and Tachenius. In the 17th century, it was named arcanuni or sal duplicatum, as it was a combination of an acid salt with an alkaline salt. It was also known as vitriolic tartar and Glaser's salt or sal polychrestum Glaseri after the pharmaceutical chemist Christopher Glaser who prepared it and used medicinally. [4] [5]

Known as arcanum duplicatum ("double secret") or panacea duplicata in pre-modern medicine, it was prepared from the residue ( caput mortuum ) left over from the production of aqua fortis (nitric acid, HNO3) from nitre (potassium nitrate, KNO3) and oil of vitriol (sulphuric acid, H2SO4) via Glauber's process:

2 KNO3 + H2SO4 → 2 HNO3 + K2SO4

The residue was dissolved in hot water, filtered, and evaporated to a cuticle. It was then left to crystallise. It was used as a diuretic and sudorific. [6]

According to Chambers's Cyclopedia , the recipe was purchased for five hundred thalers by Charles Frederick, Duke of Holstein-Gottorp. Schroder, the duke's physician, wrote wonders of its great uses in hypochondriacal cases, continued and intermitting fevers, stone, scurvy, and more. [6]

Natural resources

The mineral form of potassium sulfate, arcanite, is relatively rare. Natural resources of potassium sulfate are minerals abundant in the Stassfurt salt. These are cocrystallizations of potassium sulfate and sulfates of magnesium, calcium, and sodium.

Relevant minerals are:

The potassium sulfate can be separated from some of these minerals, like kainite, because the corresponding salt is less soluble in water.

Kieserite, MgSO4·H2O, can be combined with a solution of potassium chloride to produce potassium sulfate.

Production

Approximately 1.5 million tons were produced in 1985, typically by the reaction of potassium chloride with sulfuric acid, analogous to the Mannheim process for producing sodium sulfate. [7] The process involves intermediate formation of potassium bisulfate, an exothermic reaction that occurs at room temperature:

KCl + H2SO4 → HCl + KHSO4

The second step of the process is endothermic, requiring energy input:

KCl + KHSO4 → HCl + K2SO4

Structure and properties

Two crystalline forms are known. Orthorhombic β-K2SO4 is the common form, but it converts to α-K2SO4 above 583 °C. [7] These structures are complex, although the sulfate adopts the typical tetrahedral geometry. [8]

It does not form a hydrate, unlike sodium sulfate. The salt crystallizes as double six-sided pyramids, classified as rhombic. They are transparent, very hard and have a bitter, salty taste. The salt is soluble in water, but insoluble in solutions of potassium hydroxide (sp. gr. 1.35), or in absolute ethanol.

Uses

The dominant use of potassium sulfate is as a fertilizer. K2SO4 does not contain chloride, which can be harmful to some crops. Potassium sulfate is preferred for these crops, which include tobacco and some fruits and vegetables. Crops that are less sensitive may still require potassium sulfate for optimal growth if the soil accumulates chloride from irrigation water. [9]

The crude salt is also used occasionally in the manufacture of glass. Potassium sulfate is also used as a flash reducer in artillery propellant charges. It reduces muzzle flash, flareback and blast overpressure.

It is sometimes used as an alternative blast media similar to soda in soda blasting as it is harder and similarly water-soluble. [10]

Potassium sulfate can also be used in pyrotechnics in combination with potassium nitrate to generate a purple flame.

A 5% solution of potassium sulfate was used in the beginning of the 20th century as a topical mosquito repellent.[ citation needed ]

Reactions

Acidification

Potassium hydrogen sulfate (also known as potassium bisulfate), KHSO4, is readily produced by reacting K2SO4 with sulfuric acid. It forms rhombic pyramids, which melt at 197 °C (387 °F). It dissolves in three parts of water at 0 °C (32 °F). The solution behaves much as if its two congeners, K2SO4 and H2SO4, were present side by side of each other uncombined; an excess of ethanol the precipitates normal sulfate (with little bisulfate) with excess acid remaining.

The behavior of the fused dry salt is similar when heated to several hundred degrees; it acts on silicates, titanates, etc., the same way as sulfuric acid that is heated beyond its natural boiling point does. Hence it is frequently used in analytical chemistry as a disintegrating agent. For information about other salts that contain sulfate, see sulfate.

Related Research Articles

<span class="mw-page-title-main">Sulfuric acid</span> Chemical compound (H₂SO₄)

Sulfuric acid or sulphuric acid, known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula H2SO4. It is a colorless, odorless, and viscous liquid that is miscible with water.

The term chloride refers to a compound or molecule that contains either a chlorine ion, which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond. Many inorganic chlorides are salts. Many organic compounds are chlorides. The pronunciation of the word "chloride" is.

<span class="mw-page-title-main">Magnesium sulfate</span> Chemical compound with formula MgSO4

Magnesium sulfate or magnesium sulphate is a chemical compound, a salt with the formula MgSO4, consisting of magnesium cations Mg2+ (20.19% by mass) and sulfate anions SO2−4. It is a white crystalline solid, soluble in water but not in ethanol.

<span class="mw-page-title-main">Potassium chlorate</span> Chemical compound

Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most important application is in safety matches. In other applications it is mostly obsolete and has been replaced by safer alternatives in recent decades. It has been used

<span class="mw-page-title-main">Lead(II) sulfate</span> Chemical compound

Lead(II) sulfate (PbSO4) is a white solid, which appears white in microcrystalline form. It is also known as fast white, milk white, sulfuric acid lead salt or anglesite.

Sulfur trioxide (alternative spelling sulphur trioxide, also known as nisso sulfan) is the chemical compound with the formula SO3. It has been described as "unquestionably the most [economically important]" sulfur oxide. It is prepared on an industrial scale as a precursor to sulfuric acid.

<span class="mw-page-title-main">Calcium sulfate</span> Laboratory and industrial chemical

Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. It has many uses in industry. All forms are white solids that are poorly soluble in water. Calcium sulfate causes permanent hardness in water.

<span class="mw-page-title-main">Sodium sulfate</span> Chemical compound with formula Na2SO4

Sodium sulfate (also known as sodium sulphate or 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 as a filler in the manufacture of powdered home laundry detergents and in the Kraft process of paper pulping for making highly alkaline sulfides.

<span class="mw-page-title-main">Potassium dichromate</span> Chemical compound

Potassium dichromate, K2Cr2O7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health. It is a crystalline ionic solid with a very bright, red-orange color. The salt is popular in laboratories because it is not deliquescent, in contrast to the more industrially relevant salt sodium dichromate.

Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.

<span class="mw-page-title-main">Ammonium sulfate</span> Chemical compound

Ammonium sulfate (American English and international scientific usage; ammonium sulphate in British English); (NH4)2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen and 24% sulfur.

In chemistry, a strong electrolyte is a solute that completely, or almost completely, ionizes or dissociates in a solution. These ions are good conductors of electric current in the solution.

<span class="mw-page-title-main">Sodium bisulfate</span> Chemical compound

Sodium bisulfate, also known as sodium hydrogen sulfate, is the sodium salt of the bisulfate anion, with the molecular formula NaHSO4. Sodium bisulfate is an acid salt formed by partial neutralization of sulfuric acid by an equivalent of sodium base, typically in the form of either sodium hydroxide (lye) or sodium chloride (table salt). It is a dry granular product that can be safely shipped and stored. The anhydrous form is hygroscopic. Solutions of sodium bisulfate are acidic, with a 1M solution having a pH of slightly below 1.

<span class="mw-page-title-main">Potassium bisulfate</span> Chemical compound

Potassium bisulfate (potassium bisulphate) is an inorganic compound with the chemical formula KHSO4 and is the potassium acid salt of sulfuric acid. It is a white, water-soluble solid.

<span class="mw-page-title-main">Beryllium hydroxide</span> Chemical compound

Beryllium hydroxide, Be(OH)2, is an amphoteric hydroxide, dissolving in both acids and alkalis. Industrially, it is produced as a by-product in the extraction of beryllium metal from the ores beryl and bertrandite. The natural pure beryllium hydroxide is rare (in form of the mineral behoite, orthorhombic) or very rare (clinobehoite, monoclinic). When alkali is added to beryllium salt solutions the α-form (a gel) is formed. If this left to stand or boiled, the rhombic β-form precipitates. This has the same structure as zinc hydroxide, Zn(OH)2, with tetrahedral beryllium centers.

<span class="mw-page-title-main">Potassium persulfate</span> Chemical compound

Potassium persulfate is the inorganic compound with the formula K2S2O8. Also known as potassium peroxydisulfate, it is a white solid that is sparingly soluble in cold water, but dissolves better in warm water. This salt is a powerful oxidant, commonly used to initiate polymerizations.

<span class="mw-page-title-main">Potassium pyrosulfate</span> Chemical compound

Potassium pyrosulfate, or potassium disulfate, is an inorganic compound with the chemical formula K2S2O7.

Rubidium hydrogen sulfate, sometimes referred to as rubidium bisulfate, is the half neutralized rubidium salt of sulfuric acid. It has the formula RbHSO4.

<span class="mw-page-title-main">Leonite</span> Hydrated double sulfate of magnesium and potassium

Leonite is a hydrated double sulfate of magnesium and potassium. It has the formula K2SO4·MgSO4·4H2O. The mineral was named after Leo Strippelmann, who was director of the salt works at Westeregeln in Germany. The mineral is part of the blodite group of hydrated double sulfate minerals.

References

  1. ↑ Patnaik, Pradyot (2002). Handbook of Inorganic Chemicals. McGraw-Hill. ISBN   978-0-07-049439-8.
  2. ↑ Windholtz, M; Budavari, S, eds. (1983). The Merck Index. Rahway, New Jersey: Merck & Co.
  3. ↑ Chambers, Michael. "Potassium sulfate RN: 7778-80-5". ChemIDplus. United States National Library of Medicine.
  4. ↑ De Milt, Clara (1942). "Christopher Glaser". Journal of Chemical Education. 19 (2): 53. Bibcode:1942JChEd..19...53D. doi:10.1021/ed019p53.
  5. ↑ van Klooster, H. S. (1959). "Three centuries of Rochelle salt". Journal of Chemical Education. 36 (7): 314. Bibcode:1959JChEd..36..314K. doi:10.1021/ed036p314.
  6. 1 2 PD-icon.svg  Chambers, Ephraim, ed. (1728). "Arcanum duplicatum". Cyclopædia, or an Universal Dictionary of Arts and Sciences . Vol. 1 (1st ed.). James and John Knapton, et al. p. *125.
  7. 1 2 Schultz, H.; Bauer, G.; Schachl, E.; Hagedorn, F.; Schmittinger, P. (2005). "Potassium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_039. ISBN   3527306730.
  8. ↑ Gaultier, M.; Pannetier, G. (1968). "Structure cristalline de la forme 'basse température' du sulfate de potassium K2SO4-beta" [Crystal structure of the "low temperature" β-form of potassium sulfate]. Bulletin de la Société Chimique de France (in French). 1: 105–112.
  9. ↑ United Nations Industrial Development Organization; International Fertilizer Development Center (1998). Fertilizer manual (3rd ed.). Dordrecht, Netherlands: Kluwer Academic. ISBN   978-0-7923-5032-3.
  10. ↑ "Super K (Potassium Sulphate)". American Surface Prep. Archived from the original on 9 December 2014. Retrieved 7 December 2014.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.