The potassium sulfate is a white or colorless inorganic salt whose chemical formula is KtwoSW4. It was already known in the fourteenth century, being called in the seventeenth century as salt duplicatum, since it is a combination of an acid salt and an alkaline salt..
Potassium sulfate is found in the mineral form in arcanite, but its presentation is more common in the so-called Stassfurt salts. These are co-crystallizations of potassium, magnesium, calcium and sodium sulfates, observable in minerals such as leonite and polyhalite..
Potassium sulfate is a low-toxic salt and only causes irritation on contact with the eyes, the respiratory tract, or the digestive tract. There is no evidence of a carcinogenic or mutagenic action.
Potassium sulfate is used as a fertilizer, especially in crops that are susceptible to chlorides; such is the case of tobacco and potatoes. The compound provides potassium, one of the three main nutrients in plants, and sulfur, which is present in their proteins..
Article index
In the first image the structural formula of potassium sulfate was shown. For each SO anion4two-, of tetrahedral geometry, there are two cations K+, which can be represented by purple spheres (upper image).
Thus above we have the orthorhombic crystal structure of KtwoSW4, with SO anions4two- represented by yellow and red spheres; while the K cations+, already said, they are the purple spheres (a little more robust).
This representation can cause confusion if you think that the bars really correspond to coordination links. Rather, they indicate which ion interacts directly or closely with another around it. That is why each oxygen "connects" with five K+ (OR3SWtwo-- K+), and these in turn with ten oxygens from other surrounding sulfate anions.
There is then a somewhat "rare" coordination sphere for potassium in KtwoSW4:
This crystalline structure corresponds to polymorph β-KtwoSW4. When heated to 583 ºC, a transition to the α-K phase occurstwoSW4, which is hexagonal.
Certainly the structure of KtwoSW4 it is unusually complicated for an inorganic salt. Its ions are positioned forming a kind of meaningless tangle and, to the naked eye, lacking periodicity.
Those who dedicate themselves to crystallography can approach this tangle in a more appropriate and descriptive way, observing it from the three spatial axes.
Note that its tangled structure could explain why the KtwoSW4 does not form hydrates: H moleculestwoOr they have no way to penetrate the crystal lattice to hydrate potassium cations.
Also, with so many interactions encompassed in the ion tangle, it is to be expected that this crystal lattice will have quite a stability against heat; and in fact this is the case, since the melting point of KtwoSW4 is 1,069 ºC, which shows that its ions are strongly cohesive.
-Potassium sulfate
-Sulfate of potash
-Arcanite
-Sulfur potash
174.259 g / mol
White, odorless, bitter-tasting crystal solid, granules or powder.
2.66 g / cm3
1,069 ºC
1,689 ºC
111 g / L at 20 ºC
120 g / L at 25 ºC
240 g / L at 100 ºC
The solubility in water decreases due to the presence of potassium chloride, KCl or ammonium sulfate, (NH4)twoSW4, due to common ion effect.
Slightly soluble in glycerol, but insoluble in acetone and carbon sulfide.
1,495
Potassium sulfate can react with sulfuric acid, acidifying to form potassium bisulfate (KHSO4). It can be reduced at high temperatures to potassium sulfide (KtwoS).
Potassium sulfate is synthesized by reacting potassium chloride with sulfuric acid. The synthesis of potassium sulfate occurs in two steps. The first step involves the formation of potassium bisulfate.
This is an exothermic reaction as it releases heat and therefore does not require an external heat supply. The reaction is carried out at room temperature.
KCl + HtwoSW4 => HCl + KHSO4
The second step of the reaction is endothermic, that is, it requires the supply of heat so that it can occur.
KCl + KHSO4 => HCl + KtwoSW4
Potassium sulfate can be synthesized by the neutralization reaction of sulfuric acid with a base, potassium hydroxide:
HtwoSW4 + 2 KOH => KtwoSW4 + 2 htwoOR
Potassium sulfate is produced by the reaction of sulfur dioxide, oxygen, potassium chloride and water.
Potassium sulfate is produced by extracting the potassium sulfate present in a brine from the Loop Nur basin, China. Potassium sulfate is separated from the insoluble components of the brine by adding the acidifying compound sodium tripolyphosphate / urea phosphate.
This compound increases the difference between the solubility of potassium sulfate and the solubility of the other less soluble compounds, achieving, according to the creators of the method, a 100% pure potassium sulfate. In a strict sense it is not a synthesis method, but it is a novel extraction method.
The use of potassium sulfate as a fertilizer is its main application. 90% of its total production is used for this purpose. Its use is preferred to that of potassium chloride in those crops that are sensitive to the presence of chloride in the soil; for example tobacco.
Potassium sulfate has a potassium content of 40-44%, while its sulfur concentration represents 17-18% of the compound. Potassium is necessary to perform many essential functions for plants, since it activates enzymatic reactions, protein synthesis, starch formation, etc..
In addition, potassium is involved in regulating the flow of water in the leaves. Sulfur is necessary for protein synthesis, since it is present in amino acids that possess it; such is the case of methionine, cysteine and cystine, and it also intervenes in enzymatic reactions.
Even potassium sulfate is used by spraying on the leaves in potassium sulfate particles smaller than 0.015 mm.
Crude potassium sulfate is used in the manufacture of glass and in the manufacture of alum and potassium carbonate. It is used as a reagent in the manufacture of cosmetics. It is used in the manufacture of beer as a water corrective agent.
It is used to correct a severe decrease in plasma potassium concentration (hypokalemia), caused by excessive use of diuretics that increase urinary potassium excretion..
Potassium is the main intracellular ion of excitable cells, including heart cells. Therefore, a severe decrease in potassium in plasma compromises cardiac function, and must be corrected immediately..
Potassium sulfate has a cathartic action, that is, it favors the expulsion of stool from the colon. For this reason, a mixture of potassium, magnesium and sodium sulfates is used to clear the colon of stool before performing a colonoscopy, which allows a better visualization of the colon by the doctor..
Potassium sulfate has been used to decrease the methionine requirement in poultry feed. The presence of 0.1% potassium sulfate in the feed of laying hens is associated with a 5% increase in egg production.
It is a flavoring agent that gives foods a bitter and salty taste that is desirable in some of them. In addition, it is noted that potassium sulfate is endowed with the four basic flavors: sweetness, bitterness, acidity and salinity..
Salinity, acidity and bitterness increase with the concentration of potassium sulfate, while sweetness decreases.
Potassium sulfate is used as a pyrotechnic, in combination with potassium nitrate, to generate a purple flame. Used as a flash reducer in artillery thruster charges.
In addition, it is used as a viscosity-increasing agent in cosmetic products such as facial creams..
Potassium sulfate is a low toxic compound with a very low lethality. The LD50 for the oral dose in mice is 6,600 mg / kg of animal weight, which indicates that a high dose is required to cause the death of the mouse. The same LD50 value occurs in rats.
In the eyes, on contact, potassium sulfate can cause mechanical irritation. On the skin, potassium sulfate causes little damage to industrial handling..
If swallowed, potassium sulfate can cause gastrointestinal irritation with nausea, vomiting, and diarrhea. And lastly, inhalation of potassium sulfate dust causes respiratory tract irritation..
Yet No Comments