Sodium potassium tartrate tetrahydrate Rochelle salt

The physical phenomenon of ferroelectricity-initially termed Seignette electric-ity-was first discovered in sodium potassium tartrate tetrahydrate (Rochelle or Seignette salt), and later in analogy to ferromagnetic behavior coined ferroelectricity by Valasek (1924). Its history is listed in Table 8.4, which shows the impressive change from a curious isolated property to a widespread and economically enormously important and promising ceramic engineering material (Cross and Newnham, 1987). 

Rochelle salt (sodium potassium tartrate - tetrahydrate)... 

Ferroelectric behaviour is limited to certain materials and to particular temperature ranges for a given material. As shown for barium titanate in Section 2.7.3, Fig. 2.40(c), they have a Curie point Tc, i.e. a temperature at which the spontaneous polarization falls to zero and above which the properties change to those of a paraelectric (i.e. a normal dielectric). A few ferroelectrics, notably Rochelle Salt (sodium potassium tartrate tetrahydrate (NaKC406.4H20)) which was the material in which ferroelectric behaviour was first recognized by J. Yalasek in 1920, also have lower transitions below which ferroelectric properties disappear. 

Sodium potassium tartrate (10%). Dissolve 10 g sodium potassium tartrate tetrahydrate, KNaC4H406.4H20 (Rochelle salt or Seignette salt), in water and dilute to 100 ml. 

Beevers, C. A., and Hughes, W. The crystal structure of Rochelle salt (sodium potassium tartrate tetrahydrate NaKC4H4O6-4H30). Proc. Roy. Soc. (London) A177, 251-259 (1941). 

Rochelle salt (Sodium potassium tartrate tetrahydrate). 

Synonyms 2,3-Dihydroxybutanedioic acid, monopotassium monosodium salt Monopotassium monosodium tartrate Potassium sodium L-(+)-tartrate Potassium sodium tartrate anhydrous Rochelle salt Seignette salt Sodium potassium tartrate Classification Organic salt Definition Sodium potassium salt of L-tartaric acid avail, as the tetrahydrate Empirical C4H4KNaOe Formula KNaC4H40e... 

Synonyms Monopotassium monosodium tartrate tetrahydrate Rochelle salt Seignette salt Sodium potassium tartrate Empirical C4H4KNa06 4H2O... 

Piezoelectricity, from Greek Klet elv meaning to press, to squeeze [41], is the interplay between mechanical and electrical features of a material or a device. Changing one will impact the other. There are different types of materials that show these properties. Quartz, topaz, and tourmaline minerals human and animal bone tissue different proteins Rochelle salts (sodium, potassium tartrate tetrahydrate) barium titanate, lead zirconate titanate, PZT and the polymer poly (vinyUdene fluoride) (PVDF), are some examples. Piezoelectricity, compared to many other areas of science, was relatively recently discovered, by Jacques and Pierre Curie [42] working with quartz among other minerals. 

Rochelle salt Potassium sodium tartrate tetrahydrate, KNaC4H40e.4H20. A colourless crystalline salt used for its piezoelectric properties, it was first prepared at La Rocelle in France. 

Ferroelectrics are materials with built-in spontaneous, permanent electric polarization. Similarly as ferromagnetics possess the spontaneous, permanent magnetization, ferroelectrics have spontaneous polarization, which can be reversed by applying external electric field. The most known ferroelectrics are inorganic monocrystals, such as Rochelle salt (potassium sodium tartrate tetrahydrate... 

Fehling s solution is prepared by dissolution of Seignette s salt (still named Rochelle s salt) in an alkaline solution of copper(II) sulfate. Seignette s salt is the sodium and potassium double tartrate. It is a tetrahydrate. 

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