Niobate, potassium sodium

Simple ABO compounds in addition to BaTiO are cadmium titanate [12014-14-17, CdTiO lead titanate [12060-00-3] PbTiO potassium niobate [12030-85-2] KNbO sodium niobate [12034-09-2], NaNbO silver niobate [12309-96-5], AgNbO potassium iodate [7758-05-6], KIO bismuth ferrate [12010-42-3], BiFeO sodium tantalate, NaTaO and lead zirconate [12060-01 -4], PbZrO. The perovskite stmcture is also tolerant of a very wide range of multiple cation substitution on both A and B sites. Thus many more complex compounds have been found (16,17), eg, (K 2 i/2) 3 ... 

Only certain types of crystalline materials can exhibit second harmonic generation (61). Because of symmetry considerations, the coefficient must be identically equal to zero in any material having a center of symmetry. Thus the only candidates for second harmonic generation are materials that lack a center of symmetry. Some common materials which are used in nonlinear optics include barium sodium niobate [12323-03-4] Ba2NaNb O lithium niobate [12031 -63-9] LiNbO potassium titanyl phosphate [12690-20-9], KTiOPO beta-barium borate [13701 -59-2], p-BaB204 and lithium triborate... 

Sodium niobate(7 6) [12201 -59-17, 7Na20 6Nb20 3IH2O or Naj4Nbj2 037-31H2 0, forms a crystalline precipitate when a hot solution of a soluble niobium compound is added to a hot concentrated sodium hydroxide solution. It is insoluble in the presence of excess sodium hydroxide but is sparingly soluble in pure water. It also can be formed by addition of sodium hydroxide or chloride to a solution of the 4 3 potassium niobate. 

Tantalum can be separated from niobium by recrystallization of the double potassium fluorides. In the commercial process the ore is fused with caustic soda. The insoluble sodium niobate, sodium tantalate, and... 

Niobates are usually insoluble in water even many of the alkali niobates are insoluble. Insoluble alkali niobates are formed when niobium pentoxide is fused with only small proportions of alkali carbonate. 7 6 Sodium niobate, 7Na20.6Nb205. H20, is insoluble in solutions of high sodium-ion concentration, and is therefore precipitated. by the addition of sodium salts to solutions of potassium niobate. Ammonium niobates are unknown when excess of an ammonium salt is added to a solution of an alkali niobate, a voluminous precipitate is thrown down which is rapidly decomposed by water to yield niobic 1 Larsson, Zeitsck. anorg. Ch m., 1896,12,197. 

Potassium Niobates are generally produced by fusion of the metal or the pentoxide with potassium hydroxide, potassium carbonate, or potassium nitrate,3 or by the action of solutions of caustic potash or of potassium carbonate on niobic acid.4 They are among the most stable of the niobates their solutions can be boiled without precipitation of the acid. On being treated with sodium salts, for example sodium chloride, sodium niobates are precipitated. 

Oxysulphides.—The action of carbon bisulphide vapour or hydrogen sulphide on niobium pentoxide, sodium niobate or niobium oxytrichloride gives rise to a black powder which assumes a metallic appearance on being rubbed, and which conducts electricity well. This is probably an oxysulphide of niobium, Nba.OJ,Sz, but its exact composition varies with the experimental conditions, and its individuality is a matter of doubt.5 Oxysulphides of niobium of doubtful composition, mixed with potassium sulphide, are also produced by the action of carbon bisulphide vapour on potassium oxalo-niobate. ... 

Barium sodium niobate (BSN) Ba NaNbOj Potassium niobate KNbO,... 

Conversion of the potassium niobate/tantalate solution to the corresponding oxides is via the insoluble sodium niobate and tantalate. These are readily precipitated by the addition of a sodium salt, solid crystalline sodium chloride being preferred in economic grounds, i.e. ... 

Since the electro-optic tensor has the same symmetry as the tensor of the inverse piezoelectric effect, the linear electro-optic (Pockels) effect is confined to the symmetry groups in which piezoelectricity occurs (see Table 8.3). The electro-optic coefficients of most dielectric materials are small (of the order of 10 m V ), with the notable exception of ferroelectrics such as potassium dihydrogen phosphate (KDP KH2PO4), lithium niobate (liNbOs), lithium tantalate (LiTaOs), barium sodium niobate (Ba2NaNb50i5), or strontium barium niobate (Sro.75Bao.25Nb206) (Zheludev, 1990). For example, the tensorial matrix of KDP with symmetry group 42m has the form... 

Potassium sodium strontium niobate (K Nai.J 4(SrjBa,.p 8 NbjO KNSBN Czochralski s technique... 

Cadmium Metaniobate.—The anhydrous salt, Cd0.Nb205, is obtained by fusing potassium niobate with cadmium chloride. It forms yellowish-brown, glistening crystals, the density of which is 5-93.4 The hydrated salt Cd0.Nb20s.3 H20 is thrown down as a pale yellow precipitate on adding a solution of a cadmium salt to sodium metaniobate.8... 

Oxalo-niobates or niobo-oxalates correspond to the vanado-oxalates, and contain both oxalic acid and niobic add radicals in the complex anion. The only known series possesses the general formula 3R aO. Nb 205.6C203.a H20, where R stands for an alkali metal. The sodium, potassium and rubidium salts are prepared by fusing one molecular proportion of niobium pentoxide with three molecular proportions of the alkali carbonate in a platinum crucible. The aqueous extract of the melt jjs poured into hot oxalic add solution concentration and cooling, or addition of alcohol or acetone, then brings about precipitation of the complex salt. Comparison of the dectrical conductivity measurements of solutions of the alkali oxalo-niobates with those of the alkali hydrogen oxalates determined under the same conditions indicates that the oxalo-niobates are hydrolysed in aqueous solution, and that their anions contain a complex oxalo-niobic acid radical.6... 

Sodium Oxalo-niobate, 3Na20.Nb205.6C20s.8H20, is similar to the potassium salt, but displays a greater tendency to form supersaturated solutions. 

There are two principal types of materials that can function as piezoelectrics the ceramics and polymers. The piezoelectric materials most widely used are the piezoceramics based on the lead zirconate titanate, PZT, formations, mixed sodium and potassium niobates, lithium niobate, and quartz. The advantages of these piezoceramics are that they have a high piezoelectric activity and they can be fabricated in many different shapes. 

M. Ichiki, L. Zhang, M. Tanaka, and R. Maeda, Electrical properties of piezoelectric sodium-potassium niobate, J. Eur. Ceram. Soc., 24 1693-1697 (2004). 

The present paper considers piezoelectric ceramics as key functional material in composites and structures. Most of piezoelectrics presently exploited commercially are solid solutions based on lead zirconate titanate (PZT) ceramics. Still, compositional developments within the PZT family are performed to meet custom requirements perfectly. Lead flee piezoelectrics, such as the sodium potassium niobate solid solutiom and bismuth sochum titanate solid solutions became the topic of much research at the end of the 1990s, which is due to increased environmental avrareness. ... 

Lead zirconate titanate (PZT), barium titanate (BaTiOs), lead titanate (PbTiOs), potassium niobate (KNbOa), lithium niobate (LiNbOs), lithium titanate (LiTaOs), sodium tungstate (Na2W03) and zinc oxide (ZnO) are some of the most typical piezoceramics. Of these, PZT is the most widely used due to its superior performance. However, the toxicity of lead has raised concerns over the use of PZT. A restriction on the amount of lead present has been placed and is focused at eliminating its use eventually. Nevertheless, PZT has no rival at present. 

The MRVjOy (M = alkali metal) compounds have two structure types pyro-chlore and weberite (Chincholar, 1972). The pyrochlore structure is formed with lithium and for smaller rare earths also with sodium. The potassium compounds and sodium compounds with larger rare earth ions seem to have weberite structure, which is an orthorhombic distortion of cubic pyrochlore (Gabe and Chincolkar, 1979). The corresponding pentavalent niobates and tantalates have similar structural behaviour to the vanadates. 

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