Lanthanum nitrate, analysis

Lanthanum nitrate, analysis of anhydrous, 5 41 Lead (IV) acetate, 1 47 Lead(II) 0,0 -diethyl dithiophos-phate, 6 142 Lead (IV) oxide, 1 45 Lead(II) thiocyanate, 1 85 Lithium amide, 2 135 Lithium carbonate, formation of, from lithium hydroperoxide 1-hydrate, 5 3 purification of, 1 1 Lithium chloride, anhydrous, 6 154 Lithium hydroperoxide 1-hydrate, 5 1... 

The most popular device for fluoride analysis is the ion-selective electrode (see Electro analytical techniques). Analysis usiag the electrode is rapid and this is especially useful for dilute solutions and water analysis. Because the electrode responds only to free fluoride ion, care must be taken to convert complexed fluoride ions to free fluoride to obtain the total fluoride value (8). The fluoride electrode also can be used as an end poiat detector ia titration of fluoride usiag lanthanum nitrate [10099-59-9]. Often volumetric analysis by titration with thorium nitrate [13823-29-5] or lanthanum nitrate is the method of choice. The fluoride is preferably steam distilled from perchloric or sulfuric acid to prevent iaterference (9,10). Fusion with a sodium carbonate—sodium hydroxide mixture or sodium maybe required if the samples are covalent or iasoluble. 

Praseodymium, separation of mixtures with lanthanum from monazite, as magnesium nitrate double salt, 2 56, 67 Praseodymium (III) nitrate, analysis of anhydrous, 5 41 Praseodymium (III) oxide, for synthesis of nitrate, 5 39w. Precipitates, apparatus for removing liquid from, 8 16 Purpureochromic chloride, 2 196 6 138... 

Potassium analysis is usually carried out by flame spectrometry. Atomic emission spectrometry (AES) is slightly more sensitive, though atomic absorption spectrometry (AAS) is somewhat more immune to interference. Interferences occur in the presence of high concentrations of sodium and due to the formation of refractory potassium phosphates in the flame. A solution containing 0.4 mmol cesium chloride and 0.15 mmolL lanthanum nitrate dissolved in 0.1 M HCl will reduce both cation enhancement and anionic suppression (Wieland 1992, Birch and Padgham 1993). 

Sometimes, small differences in stoichiometry that would not readily be detected by analysis are revealed by crystallography. For example, crystals of two lanthanum nitrate complexes of the terdentate 4-amino-bis(2,6-(2-pyridyl))-l,3,5-triazine, 10- and 11-coordinate [La(abptz)(N03)3(H20) ] (n = 1, 2), can be isolated from the same reaction mixture, evidently because of similar solubilities. This subtle difference in stoichiometry leads to significant differences in the molecular geometry. Thus, the increase in coordination number of the lanthanum from 10 to 11 is accompanied by a sharp increase in La-0... 

Fluoride samples of high concentration can be titrated potentiometrically [60] with lanthanum nitrate or thorium nitrate reagent. The potentiometric standard addition technique with NaF standard solution [61] also was found applicable however, direct potentiometry using calibration curves is most often relied on in water analysis. 

The bicycUc polyethers give rise to complex structures. With lanthanum chloride and Bicy(4,2B,2B), the adduct corresponds approximately to a 1 1 stoichiometry, but a crystalline product is obtained only in the presence of water. The crystal structure analysis shows that partial hydrolysis takes place. In this, the behaviour is reminiscent of the 2 1 TEA complexes with 15C5. Indeed, the unit cell contains a pseudo-centrosymmetric dimer [LaCl(Cl,OH)L]2 with an OH Cl hydrogen bond across the centre of symmetry one site is occupied by Cl in one half and by OH in the other half. The ligand in this structure has an approximate twofold axis of symmetry. The O atoms form an end-capped trigonal prism around La(III) and the metal ion lies in the mean plane formed by the O atoms of the aliphatic unsubstituted chain. The other bicyclic polyether, Bicy(4B,2B,2B), forms 3 2 complexes with lanthanum nitrate. The asymmetric unit contains two dinitrato cations [La(N03)2L] and one pentanitrato anion [La(N03)5(Me0H)] . The La(III) ion is 11-coordinate in the anion and one of the cations, in which there is one bidentate and one monodentate nitrate ion. It is 12-coordinate in the other cation. 

ScF3 and LaF3. Both separate and multilayer scandium and lanthanum fluoride films have been grown from nitrates and lanthanum chloride and sodium and ammonium fluorides. XPS analysis revealed that the films were stoichiometric and that the films contained both hydroxide groups and water.129... 

The nitrate is used as an analytical standard as a matrix modifier in furnace AA analysis and for preparing other lanthanum salts. 

Kosinski and Bostian (12) reported the extraction of lanthanum by HDEHP from aqueous nitrate solutions over a wide concentration range. Using mass balance data and IR analysis of the organic phase, they proposed three extraction reactions which occur simultaneously ... 

For example, in the determination of the atomic weight of lanthanum the salt lanthanum ammonium nitrate was recrystallized from water 126 times, eadi crystallization involving the separation of die material into as many as 12 fractions. Analysis of the final fraction showed constancy of composition to 1 part in 20,000. Lanthanum compounds, like other rare-earth compounds, are hard to purify because corresponding compounds of the rare-earth metals differ only slightly from one another in properties. 

Polycrystalllne samples of LaSrAlCu05 were prepared by solid state reaction of Aldrich cupric oxide (99.999%), strontium carbonate (99.999%), lanthanum oxide (99.999%) and aluminum nitrate (99.999%). Powders were ground with a mortar and pestle and calcined In air at 950 C for 5 days with dally grindings. The product was dark black. Thermogravlmetrlc studies with a Du Pont Thermal Analysis System by reduction In hydrogen were used to determine the oxygen composition. 

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