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Potassium sodium tartrate has a specific gravity of about 1.79, a melting point of approximately 75°C, and has a saline, cooling taste, as a food additive, its E number is E337.
Potassium sodium tartrate has been used medicinally as a laxative.
Potassium sodium tartrate has also been used in the process of silvering mirrors.
CAS Number: 304-59-6
Molecular Formula: C4H6O6.K.Na
Molecular Weight: 212.18
EINECS Number: 206-156-8
Synonyms: Rochelle salt, Seignette salt, SODIUM POTASSIUM TARTRATE, 304-59-6, Monopotassium monosodium tartrate, Sodium potassium L-tartrate, Potassium sodium L(+)-tartrate, Potassium sodium tartrate anhydrous, Tartaric acid, monopotassium monosodium salt, P49F8NV7ES, CHEBI:63019, 2,3-Dihydroxybutanedioic acid, monopotassium monosodium salt, Butanedioic acid, 2,3-dihydroxy-, monopotassium monosodium salt, DTXSID90889341, E-337, Co eff pdr, RefChem:570851, DTXCID001323681, Butanedioic acid, 2,3-dihydroxy-(2R,3R)-, monopotassium monosodium salt, 206-156-8, 613-385-0, INS NO.337, INS-337, Potassium sodium dextro-tartrate, Potassium Sodium Tartrate, QH257BPV3J, L-Potassium sodium tartrate, 147-79-5, potassium;sodium;(2R,3R)-2,3-dihydroxybutanedioate, Sodium potassium salt of L-(+)-tartaric acid, Rochelle's salt, C4H4KNaO6, CCRIS 3949, HSDB 765, Sodium potassium (dl)-tartrate, Potassium sodium tartrate tetrahydrate, Potassium Sodium Tartrate (1.5M Solution in Water), EINECS 206-156-8, potassium sodium l-tartrate, UNII-P49F8NV7ES, Seignette's salt, EINECS 205-698-2, Tartaric acid, potassium sodium salt, MFCD00065391, potassium sodium (2R,3R)-2,3-dihydroxybutanedioate, Potassium sodium (R*,R*)-(1)-tartrate, Butanedioic acid, 2,3-dihydroxy- (2R,3R)-, monopotassium monosodium salt, L-Potassiumsodiumtartrate, L-(+)-Tartaric Acid Potassium Sodium Salt, Monopotassium monosodium 2,3-dihydroxybutanedioate, (R-(R*,R*))-, Butanedioic acid, 2,3-dihydroxy- (R-(R*,R*))-, monopotassium monosodium salt, EC 206-156-8, potassium sodium L-tartarate, orb2939272, CHEMBL2219738, SCHEMBL29350175, DTXSID60932999, Potassium Sodium L-(+)-Tartrate, AKOS015915091, POTASSIUM SODIUM TARTRATE [MI], potassium sodium tartrate tetrahy-drate, Butanedioic acid, 2,3-dihydroxy- (theta-(theta,theta))-, monopotassium monosodium salt, POTASSIUM SODIUM TARTRATE [HSDB], 15490-42-3, ANHYDROUS SODIUM POTASSIUM TARTRATE, BP-21323, P1798, F76579, ANHYDROUS SODIUM POTASSIUM TARTRATE [MART.], Potassium sodium 2,3-dihydroxybutanedioate (1/1/1), rel-Potassium sodium (2R,3R)-2,3-dihydroxysuccinate, Butanedioic acid, 2,3-dihydroxy- (2R,3R)-, potassium sodium salt (1:1:1), BUTANEDIOIC ACID, 2,3-DIHYDROXY-, (R-(R*,R*))-, MONOPOTASSIUM MONOSODIUM SALT, D-Potassiumsodiumtartrate;Potassium sodium tartarate;POTASSIUM SODIUM TARTRATE SOLUTION 1.5M;SodiumPotassiumTartarate;Butanedioic acid, 2,3-dihydroxy- (2R,3R)-, monopotassium monosodium salt;l-(+)-tartaric acid potassium sodium salt solution;potassium sodium tartrate solution;[R-(R*,R*)]-2,3-Dihydroxybutanedioic acid monopotassium monosodium salt
Potassium sodium tartrate is a double salt first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle, France. As a result the salt was known as Seignette's salt or Rochelle salt.
Potassium sodium tartrate is not to be confused with rock salt, which is simply the mineral form of sodium chloride.
Potassium sodium tartrate and mono potassium phosphate were the first materials discovered to exhibit piezo electricity.
Potassium sodium tartrate is a colorless to blue - white salt crystallizing in the orthorhombic system.
Its molecular formula is KNaC4H4O6·4H2O.
Potassium sodium tartrate is slightly soluble in alcohol but more completely soluble in water.
Potassium sodium tartrate is an ingredient of Fehling's solution, formerly used in the determination of reducing sugars in solutions.
Potassium sodium tartrate is a double salt composed of potassium tartrate and sodium tartrate.
Its chemical formula is KNaC₄H₄O₆·4H₂O, and it commonly occurs as transparent, colorless crystals.
Potassium sodium tartrate is also known as Rochelle salt or Seignette’s salt, named after the French chemist Pierre Seignette.
Potassium sodium tartrate is derived from tartaric acid, a naturally occurring organic acid found in grapes and tamarinds.
It is formed by neutralizing tartaric acid with both sodium hydroxide and potassium hydroxide.
The resulting salt combines the characteristics of both metal ions, giving it unique physical and chemical properties.
Potassium sodium tartrate is soluble in water but insoluble in alcohol and most organic solvents.
It produces a mildly alkaline solution when dissolved in water.
The crystals are slightly efflorescent, meaning they can lose water of crystallization when exposed to air.
Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a double salt of tartaric acid first prepared (in about 1675) by an apothecary, Élie Seignette [fr], of La Rochelle, France. Potassium sodium tartrate and monopotassium phosphate were some of the early materials discovered to exhibit piezoelectricity.
This property led to its extensive use in crystal phonograph cartridges, microphones and earpieces during the post-World War II consumer electronics boom of the mid-20th century.
Such transducers had an exceptionally high output with typical pick-up cartridge outputs as much as 2 volts or more.
Potassium sodium tartrate is deliquescent so any transducers based on the material deteriorated if stored in damp conditions.
It has been used medicinally as a laxative.
Potassium sodium tartrate has also been used in the process of silvering mirrors.
It is an ingredient of Fehling's solution (reagent for reducing sugars).
Potassium sodium tartrate is used in electroplating, in electronics and piezoelectricity, and as a combustion accelerator in cigarette paper.
In organic synthesis, it is used in aqueous workups to break up emulsions, particularly for reactions in which an aluminium-based hydride reagent was used.
Potassium sodium tartrate is also important in the food industry.
It is a common precipitant in protein crystallography and is also an ingredient in the Biuret reagent which is used to measure protein concentration.
This ingredient maintains cupric ions in solution at an alkaline pH.
Larger crystals of Rochelle salt have been grown under conditions of reduced gravity and convection on board Skylab.
Potassium sodium tartrate crystals will begin to dehydrate when the relative humidity drops to about 30% and will begin to dissolve at relative humidities above 84%.
Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a white crystalline solid that is very soluble in water.
Potassium sodium tartrate is free of OGM, allergens, gluten and contaminants (pesticides, dioxin, mycotoxins, PCB, antibiotics and PAH).
It is used in the food industry and as a set retarder in gypsum and cement.
Potassium sodium tartrate is used in electroplating, mirror silvering and electronics.
Potassium sodium tartrate has a molecular weight of 282.22 g/mol.
It melts at around 70°C, losing its water of crystallization in the process.
When heated strongly, it decomposes, releasing carbon dioxide and leaving behind a carbonaceous residue.
Potassium sodium tartrate crystallizes in the orthorhombic crystal system, forming prismatic, glassy crystals.
It is non-toxic and non-flammable, which makes it safe for laboratory and food applications.
However, it is slightly hygroscopic, so it must be stored in tightly closed containers to prevent moisture absorption.
One of its remarkable properties is piezoelectricity, the ability to generate an electric charge when mechanically stressed.
This effect was first discovered in Rochelle salt in the early 20th century.
It led to important developments in microphones, phonograph pickups, and crystal oscillators.
Potassium sodium tartrate is widely used as a reagent in chemical laboratories.
It serves as a complexing agent and reducing agent in analytical chemistry.
For instance, it is used in Fehling’s solution to detect the presence of reducing sugars.
It is also a component of Benedict’s solution, which performs a similar function in glucose detection.
In these reactions, the tartrate ions stabilize the copper(II) complex in an alkaline medium.
This allows the controlled reduction of copper(II) to copper(I) oxide when a reducing sugar is present.
In electroplating and metal finishing, it helps stabilize metal ions in solution.
This ensures smooth deposition of metals like silver, nickel, and copper.
It also prevents unwanted precipitation during electrochemical reactions.
Potassium sodium tartrate finds use in pharmaceuticals and food processing as well.
It acts as a sequestering and buffering agent in formulations that require pH control.
Because of its mild alkalinity and low toxicity, it is often classified as food-grade (E337).
Potassium sodium tartrate was one of the earliest known piezoelectric materials.
When subjected to mechanical pressure, it generates an electrical potential difference across its surfaces.
Conversely, when exposed to an electric field, it undergoes mechanical deformation.
This dual property makes it useful in transducers, microphones, and early crystal-based oscillators.
It was historically used in radar and sound detection devices during the mid-20th century.
Although now largely replaced by synthetic crystals like quartz, it remains significant in piezoelectric research.
Its dielectric constant varies with temperature and pressure, making it valuable for studying solid-state phenomena.
Because of its anisotropic structure, it can exhibit ferroelectric behavior under certain conditions.
This makes it a model compound in the study of phase transitions and electric polarization.
Melting point: 70~80℃
Boiling point: 100 °C
Density: 1.24
vapor pressure: 0Pa at 25℃
storage temp.: Room Temperature
solubility: Methanol, Water
form: Liquid
color: Clear Colorless
PH: 7.0-8.5 (25℃, 1.5M in H2O)
optical activity: [α]20/D +22±1°, c = 1% in H2O
Water Solubility: g anhydrous/100 g H2O: 31.9 (0°C), 67.8 (20°C), 102 (30°C) [LAN05]; slightly soluble alcohol [MER06]
λmax: λ: 260 nm Amax: 0.03
λ: 280 nm Amax: 0.025
LogP: -1.080 (est)
Potassium sodium tartrate, (KNaC4H4O6) may be prepared by adding 0.5 mole sodium carbonate to heated solution containing 1 mole potassium bitartrate(KHC4H5O6).
The solution is filtered while hot.
This solution is then dried to precipitate solid potassium sodium tartrate, as small crystallites.
Larger crystals of Potassium sodium tartrate have been grown under conditions of reduced gravity and convection on board Skylab .
Potassium sodium tartrate-based composites have gained renewed interest for their applications in impact energy absorption and smart sensing technologies.
Recent research has demonstrated the growth of Rochelle salt crystals within 3D-printed cuttlebone-inspired structures, resulting in multifunctional composites that combine mechanical robustness with piezoelectric properties.
The chambered microstructure inspired by cuttlefish bone provides high stiffness and energy absorption capacity, making these composites suitable for protective equipment and structural health monitoring.
The developed composites exhibit remarkable mechanical performance, with enhanced fracture toughness and resistance to impact.
Under cyclic loading, they maintain consistent piezoelectric output for up to 7000 cycles.
Impact tests show voltage outputs peaking at approximately 8 V, and a piezoelectric coefficient (d33) around 30 pC/N.
These properties enable real-time sensing of impact forces, making the material suitable for use in wearable protective gear, such as smart armor for athletes and fall detection devices for the elderly.
Sustainability and recyclability are notable advantages of this material.
The Rochelle salt crystals can be dissolved and re-grown within the structure, allowing the composite to be repaired after damage. Recycled samples retain up to 95% of their original mechanical and piezoelectric performance.
Potential applications extend to sports safety equipment, aerospace structures, military armor, and biomedical monitoring devices, highlighting the versatility and functionality of Rochelle salt composites in modern material science.
In the food industry, potassium sodium tartrate functions as an acidity regulator and emulsifier.
Potassium sodium tartrate helps stabilize whipped products, cream fillings, and sugar syrups.
It is assigned the food additive code E337 by the European Food Safety Authority (EFSA).
Potassium sodium tartrate can also act as a laxative or saline cathartic when used in appropriate doses.
By increasing osmotic pressure in the intestines, it promotes water retention and bowel movement.
However, excessive consumption may lead to gastrointestinal discomfort or dehydration.
In pharmaceuticals, it is used as a stabilizer for oral formulations and effervescent tablets.
Its ability to maintain solution stability and pH balance improves drug solubility.
It is also used as a buffering agent in intravenous and oral rehydration products.
Potassium sodium tartrate is generally regarded as safe and non-toxic.
However, contact with eyes or prolonged exposure to dust may cause mild irritation.
Ingestion of large amounts can lead to diarrhea or nausea due to its mild laxative action.
Environmentally, it is biodegradable and does not accumulate in soil or aquatic ecosystems.
It can be safely disposed of by dilution with water in accordance with environmental regulations.
Its low reactivity and absence of heavy metals make it environmentally friendly.
Storage should be in dry, cool conditions away from moisture and strong acids.
The compound can slowly decompose in humid air, losing its crystalline water.
Sealed packaging ensures long-term stability and effectiveness.
Potassium sodium tartrate, chemically written as KNaC₄H₄O₆·4H₂O, is a hydrated double salt formed from tartaric acid.
It belongs to the family of organic acid salts and is characterized by its ability to crystallize with four molecules of water.
These water molecules are essential for maintaining the salt’s crystal structure and physical properties.
Potassium sodium tartrate has been known since the 17th century, when it was first discovered in Rochelle, France.
This is why it is historically referred to as Rochelle salt or Seignette’s salt.
It was one of the earliest compounds used in the study of crystal symmetry and optical activity.
Potassium sodium tartrate is odorless, non-flammable, and has a cooling, saline taste.
Its crystals are transparent and have a slightly pearly luster under light.
They are moderately stable in air but can lose water and turn opaque when exposed to heat or dryness.
The crystalline structure of potassium sodium tartrate is orthorhombic, with a complex hydrogen-bonding network.
The potassium and sodium ions are held within the tartarate framework by ionic and hydrogen bonds.
These interactions create a highly ordered structure responsible for its piezoelectric and ferroelectric properties.
When heated to around 70°C, the salt loses its four molecules of crystallization water.
At temperatures above 200°C, it begins to decompose, releasing carbon dioxide and organic vapors.
During decomposition, a carbon-rich residue remains, which burns at higher temperatures.
Its density is approximately 1.79 g/cm³, and it has a refractive index of 1.49.
It dissolves readily in water, yielding a slightly alkaline solution with a pH between 7.5 and 8.5.
It is almost insoluble in ethanol, acetone, and other organic solvents.
Potassium sodium tartrate plays a critical role in qualitative and quantitative chemical analysis.
It is used to prepare Fehling’s solution, a classical reagent for detecting reducing sugars like glucose.
In this test, it stabilizes the copper(II) ions in alkaline solution, preventing their premature precipitation.
It is also used in Benedict’s solution, which functions similarly for detecting reducing sugars.
The tartrate ion complexes with copper ions, maintaining them in a soluble blue form.
When reducing sugars are present, they reduce Cu²⁺ to Cu₂O, forming a red or orange precipitate.
In electrochemical studies, potassium sodium tartrate acts as a complexing and buffering agent.
It controls the ionic balance and prevents irregular metal deposition during electroplating.
This stabilizing property makes it essential in many analytical and industrial electrochemical systems.
Uses:
Sodium Potassium Tartrate is a buffer and sequestrant that is the salt of i, (+)–tartaric acid.
It has a solubility in water of 1 g in 1 ml.
Potassium sodium tartrate is also termed rochelle salt and potassium sodium tartrate.
Potassium Sodium Tartrate Solution is a chelator used for research purposes.
Potassium sodium tartrate is an essential reagent in analytical chemistry and laboratory testing.
It is a key ingredient in Fehling’s and Benedict’s solutions, which are used to detect reducing sugars such as glucose.
In these tests, it acts as a complexing agent that stabilizes copper(II) ions in alkaline solution.
The compound prevents copper hydroxide from precipitating, allowing an accurate reaction to occur.
When reducing sugars are present, the copper(II) ions are reduced to brick-red copper(I) oxide, indicating a positive result.
Because of this stabilizing property, it is frequently used in qualitative and quantitative sugar analysis.
Potassium sodium tartrate is also used in titration and electrochemical experiments.
It serves as a buffering agent that maintains the pH of solutions during chemical reactions.
This makes it valuable in educational laboratories for teaching general chemistry principles.
In the metal finishing and electroplating industry, potassium sodium tartrate is used as a complexing and leveling agent.
It keeps metal ions like copper, nickel, and silver in stable solution during plating processes.
This ensures that metal coatings are smooth, uniform, and adherent.
It also acts as a chelating agent that binds unwanted impurities in metal baths.
By preventing precipitation, it improves the overall efficiency and quality of electroplating systems.
Hence, it is a critical additive in precision metal surface treatments.
In glass and mirror manufacturing, potassium sodium tartrate assists in the silvering process.
It helps reduce silver nitrate to metallic silver, forming a reflective coating on glass surfaces.
This reaction is used to produce mirrors, optical coatings, and decorative glass.
Potassium sodium tartrate is approved as a food additive, designated by the code E337.
It functions as a stabilizer, emulsifier, and acidity regulator in processed foods.
Its mild alkalinity helps maintain balance in foods that contain natural acids.
In confectionery and syrup production, it prevents sugar crystallization and improves texture.
This gives candies and jellies a smoother and more uniform consistency.
It is also used in baking powders and dough conditioners as part of the leavening system.
When combined with sodium bicarbonate, it releases carbon dioxide gas, helping dough rise.
This reaction gives baked goods a light and fluffy structure.
Its neutral taste makes it ideal for use in pastries, cakes, and biscuits.
In medicine, potassium sodium tartrate is used as a pharmaceutical excipient and stabilizer.
It helps maintain the pH balance and solubility of active ingredients in oral and injectable drugs.
Its buffering ability ensures that formulations remain chemically stable during storage.
It is commonly included in effervescent tablets, where it reacts with bicarbonates to produce fizz.
This aids in dissolving the medication and improving patient comfort.
It also appears in oral rehydration and electrolyte formulations for pH control.
Historically, potassium sodium tartrate was used as a mild saline laxative.
It works by increasing osmotic pressure in the intestines, drawing in water, and stimulating bowel movement.
Although safer alternatives now exist, it remains recognized for its gentle purgative effect.
Rochelle salt was one of the first materials discovered to exhibit piezoelectricity.
It can generate an electric potential when mechanical stress is applied to its crystal structure.
This property also works in reverse — it deforms mechanically under an applied electric field.
Because of this, it was widely used in microphones, phonograph pickups, and sonar transducers.
It converted sound waves into electrical signals and vice versa with high sensitivity.
Before quartz crystals were developed, Rochelle salt was the main piezoelectric material in electronics.
It is also known for its ferroelectric properties, which allow it to store electrical charge.
These characteristics made it useful in early oscillators, capacitors, and signal generators.
Even today, it is used in scientific research and educational demonstrations on piezoelectricity.
In schools and universities, potassium sodium tartrate is used for demonstrating crystal properties.
Its transparent crystals are ideal for teaching crystallography and piezoelectric effects.
It allows students to explore the relationship between structure, symmetry, and conductivity.
It is also used in thermodynamic and physical chemistry experiments.
For example, it demonstrates hydration, efflorescence, and crystal formation.
Because it is non-toxic and stable, it is safe for classroom use.
In physics and materials science, Rochelle salt is used to study ferroelectric phase transitions.
These studies contribute to the development of new smart materials and sensors.
Hence, it serves both academic and applied research purposes.
Potassium sodium tartrate can be used in mild cleaning formulations due to its chelating properties.
It removes mineral residues and scale from glass and metal surfaces.
Because it is gentle, it does not damage delicate items such as laboratory glassware or silverware.
It can also be used in homemade cleaning recipes as a non-toxic alternative to harsh chemicals.
When combined with mild acids, it helps break down stains and deposits.
Its biodegradability makes it environmentally safe for household use.
In laundry applications, it can act as a softening and pH-buffering agent.
This enhances detergent performance, especially in hard water areas.
Its natural composition aligns with eco-friendly and sustainable cleaning practices.
Potassium sodium tartrate is considered eco-friendly and biodegradable.
It is used in environmentally conscious manufacturing as a safer alternative to synthetic chelators.
Its low toxicity makes it suitable for use in green chemistry and sustainable formulations.
In wastewater treatment, it assists in the removal of heavy metals through complexation.
It binds with metal ions, forming stable compounds that can be easily filtered out.
This process reduces the environmental impact of industrial effluents.
It is also used in the preparation of biocompatible catalysts and coating materials.
Its role as a natural ligand supports reactions in the chemical, ceramic, and polymer industries.
Because of its safety and versatility, it is included in many environmental compliance systems.
Safety Profile:
Potassium sodium tartrate is considered safe for laboratory and industrial use when handled correctly.
It is non-corrosive and does not emit hazardous fumes under normal conditions.
However, direct contact with eyes or open wounds may cause mild irritation.
It should be stored in tightly sealed containers, away from moisture and high temperatures.
Prolonged exposure to humidity can cause it to absorb water and form clumps.
Dry, cool storage conditions maintain its crystalline form and purity.
From an environmental standpoint, potassium sodium tartrate is fully biodegradable.
It decomposes into carbon dioxide, water, and harmless organic residues.
Thus, it presents no significant ecological risk when disposed of properly.
Spills can be cleaned with water since the compound is non-toxic and water-soluble.
Industrial wastewater containing small amounts of the salt poses minimal hazard.
It is often used as an example of an eco-friendly industrial reagent in green chemistry discussions.
Potassium sodium tartrate is generally considered safe and non-toxic, but like all chemical compounds, it presents certain health, environmental, and handling hazards under inappropriate conditions.
Below are its hazards explained in detail and arranged in the same order as the “uses” section, with each paragraph containing three clear sentences for structured understanding.
In laboratory settings, potassium sodium tartrate is of low toxicity, but prolonged exposure to its dust can cause mild irritation.
Contact with the eyes may result in redness, tearing, or temporary discomfort.
If ingested in large amounts, it can cause nausea, diarrhea, or mild stomach upset.
When heated strongly, it decomposes and releases carbon dioxide and organic vapors, which can be irritating if inhaled.
These decomposition products are not acutely toxic but can cause respiratory irritation in unventilated spaces.
Therefore, heating or drying the salt should be done under adequate ventilation or a fume hood.
Although it is non-corrosive, it should not be stored near strong acids or oxidizers.
Such reactions could produce unwanted by-products or lead to mild exothermic reactions.
Gloves and goggles are recommended to prevent accidental exposure during analytical work.
