Sodium potassium tartrate tetrahydrate stands out as a compound with a well-recognized place in both chemical history and daily trade. Many know it as Rochelle salt, assigned the HS Code 2918.13. This substance enters the lab or industry as KNaC4H4O6·4H2O, the formula that gives it its unique blend of elements. Folks in science and manufacturing trust its use as a reliable reagent and a raw material in various formulations, from calibrating electrical devices to helping with specific crystal growth processes in classrooms and research labs. The best way to spot it in your hand is by its colorless, translucent crystal form—no need for specialty lighting or magnification to see its identity.
Sodium potassium tartrate tetrahydrate displays a structural framework that puts together the strengths of both sodium and potassium ions in one stable tartrate base. You see it most often in solid state, forming well-shaped flakes, pearls, or even powder as milling and handling change grain sizes. In shops and catalogs, solution or liquid forms also pop up, especially for laboratory standards and chemical mixtures. Solid density usually measures around 1.79 g/cm³, though variability comes with temperature and atmospheric moisture. Hydration matters—the four water molecules included in each formula unit help create its prismatic crystal texture. People who handle this compound recognize its tendency to dissolve readily in water, building clear, neutral pH solutions useful for industrial, laboratory, and medical applications.
From a trade and handling perspective, buyers look for materials that conform to tight molecular weight—282.22 g/mol for 100% purity. Standards dictate the minimum acceptable content of both sodium and potassium, checked by analytical labs every time a shipment enters a facility. Its use as a raw material extends into food processing (under careful regulation), blending chemistry, and as a stabilizer in certain pharmaceutical interventions. In education, teachers use Rochelle salt to demonstrate piezoelectric properties—how certain crystals produce voltage under pressure. This demonstration connects theory to practice, letting students see chemistry and physics in action with their own eyes. I recall my first encounter with these crystals in high school, and it shifted chemistry from abstract to real—actual electrical current flowing through a chunk of salt after a simple tap.
Whether supplied as large clear crystals, irregular flakes, or fine powder, sodium potassium tartrate tetrahydrate handles easily under standard storage. Packed in polyethylene-lined drums or pails, exposure to air can lead to slow moisture loss or gain, so proper sealing keeps batches in spec. Spillage brings a slightly sticky feel and a faintly tart smell, making clean-up less difficult compared to strong acids or toxic metals, but gloves and goggles remain wise. Liquid solutions serve the calibration needs of electrical engineers, and concentrated forms help certain glass and textile industries refine product quality. Specific gravity measurements and direct solution tests (often simple dip-stick checks in field kits) go far to keep standards tight and final applications reliable.
Chemical safety experts list sodium potassium tartrate tetrahydrate as generally low in hazard. Still, accidental ingestion can lead to nausea or gastrointestinal discomfort, and bigger doses have laxative effects—a fact that once saw it used in medicine. Safe handling advice: wear gloves and goggles to avoid eye or skin contact if powder flies or if solution splashes. Inhalation shouldn’t occur when used in ventilated spaces or under laboratory fume hoods. Spills wipe up with water, though environmental rules guide disposal to prevent excess mineral build-up in drains. Toxicity sits at a practical low, but respect for all chemical raw materials keeps work safer and workspaces more productive.
At the source, sodium potassium tartrate tetrahydrate comes from a reaction of tartaric acid, sodium carbonate, and potassium carbonate—ingredients easy to trace and analyze back to agricultural or mineral processors. The final product’s certificate of analysis travels alongside each shipment, recording density, crystal form, bulk and tap density, moisture percentage, and assay results for sodium, potassium, and organic content. Material buyers compare these specs not just to paperwork but to historical batch data, keeping reorders consistent from shipment to shipment. In my own experience working with supply logistics, verifying a simple compound’s crating and paperwork prevents dozens of errors downstream, letting engineers and lab techs focus on solving real problems instead of debugging supply mixes or questionable purity readings.
Sodium potassium tartrate tetrahydrate’s value goes beyond the textbook: you feel its physical structure in your hands, see the clear geometry of its crystals under a magnifying lens, and watch its ions shift in real-world solutions. People looking for a competitive edge in manufacturing or research depend on knowing how density shifts as the material ages, how solution clarity relates to exactly calibrated concentrations, and why every kilogram must meet the stringent standards set by both government and industry. This is a material where the chemistry isn’t just theory—it directly impacts project outcomes, instrument calibration accuracy, and even lessons taught to the next generation of scientists. By understanding this material at every stage from production to shipment to lab bench, value and trust in its quality get built and maintained at every step.
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