Sodium 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... 

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 metaniob ate (1 1) [67211-31-8] Na20 Nb20 7H20 or Na2Nb20g-7H20, separates as colorless triclinic crystals as a result of concentrating the mother Hquor from the preparation of the 7 6 sodium niobate by spontaneous evaporation. It also can be obtained by fusion of the anhydrous pentoxide in sodium hydroxide or carbonate. 

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. 

Sodium naphthalene, 74 247 Sodium naphthalene complex, 22 764 Sodium niobate, 77 153 Sodium nitrate, 22 843-853, 860-862 applications of, 22 843, 852-853 commercial grades of, 22 850t crystallization of, 22 848 deposits of, 22 843-845 described, 22 843 economic aspects of, 22 849... 

Nowadays a large number of functional crystals belongs to the TTB family and presents electro-optic, ferro- piezo- pyroelectric properties (e g. the well-known barium sodium niobate Ba2NaNb50i5 (BNN)). In this work iron and manganese based Kx(lvr%(]Vr )i-xF3 fluorides (0.4solid state reaction and characterised by different diffraction techniques in order to investigate their crystalline stmcture. 

This reaction is significant for sodium titanate (Keq — 10 moles /l ) and sodium zirconate, but is negligible for sodium niobate and some other "titanates" such as Mg(Ti205H)2. Gelatinous hydroxide precipitates which would appear likely based on Eq. 3 were not observed in the reaction of sodium titanate with aqueous waste, and stoichiometric loading was achieved with polyvalent cations which form insoluble hydroxides as well as for those forming soluble hydroxides. 

Wohlerite is a niobate of calcium, iron, manganese, sodium, etc., associated with considerable quantities of zirconia and silica. It is found in Norway. Other silicates which contain niobium or tantalum are struverite10 and ilmenorutile.11... 

Niobium Tetrachloride is reported to have been obtained in solution by the electrolytic reduction of a solution of sodium niobate in hydrochloric acid.7... 

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. 

Aluminium Niobate, A120 3.3Nb205.12HaO, is obtained as a white precipitate by the action of a solution of alum on sodium metaniobate, Na20. Nb205.7H20.2... 

Barium Niobate.—A salt having the composition 7Ba0.6Nb20s. 18H20 is prepared by treating a hot solution of the corresponding sodium salt with dilute barium chloride solution.3... 

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... 

Isomorphous mixtures of calcium niobates and sodium niobates have also been prepared.12 A ealdum niobate occurs in the mineral pyrocMore. 

Mercury Niobate.—A salt having the probable composition Hg20. Nb20B.8H20 has been obtained by the action of mercurous nitrate on sodium niobate solution.2... 

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. 

Sodium niobate, 2Na20.3Nb205.9Hg0, is said to have been prepared in small crystals by fusing niobium pentoxide with caustic soda and extracting the melt with boiling water,1 but Bedford 2 was unable to obtain the compound by this process. 

Niobic acid, or more probably add niobates, remain in solution. On the other hand, by passing a stream of carbon dioxide through an aqueous solution of the 7 6 salt, the 1 1 salt or metaniobate is precipitated these two sodium niobates hence are mutually convertible.4... 

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. 

Sodium Pemiobate, Na3Nb08, is obtained as a white powder by the action of caustic soda and 3 per cent, hydrogen peroxide on 7 6 sodium niobate. 

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. ... 

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. 

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