Tetraborate ion

Titration of borate ion with a strong acid. The titration of the tetraborate ion with hydrochloric acid is similar to that described above. The net result of the displacement titration is given by ... 

This results in narrow relaxation behaviour, as shown in Figure 5.32. The timescale of relaxation can be adjusted by altering the concentration of the tetraborate ion. 

Sahoo SK, Masuda A (1995) Simultaneous measurement of lithium and boron isotopes as lithium tetraborate ion by thermal ionization mass-spedrometry. Analyst 120 335-339... 

Tetraborate ions exhibit a similar low affinity toward the stationary phase allowing for the separation of fluoride and short-chain aliphatic carboxylic acids. Since boric acid as the suppressor product is only weakly dissociated, sodium tetraborate is also suited for gradient elution to a limited extent. 

The pO drop at the equivalence point corresponds to the ligand number 1, which confirms the running of the interaction (1.2.91) in molten Nal. This interaction is characterized by a pK value of —5.02 0.6. It should be emphasized that with the excess of the Lux acid the equilibrium is achieved slowly enough. This seems to be caused by the fact that sodium tetraborate is practically completely polymerized, although the polymerizations effects on the titration process are less pronounced than in the case of B203. After the equivalence point, with the pO drop of 3-3.5 pO units, the equilibrium conditions are achieved in a shorter period, since under these conditions all the polymerized particles are destroyed. The excess of the base over that necessary for the formation of B02 results in the fixation of O2- by the formed metaborate, which demonstrates the oxoacidic properties. The dependence of the ligand number on the initial titrant molality allows us to assume that the final product is sodium orthoborate, B03- (equation (1.2.92)), whose pK value is close to 2. All that we have said above shows that the oxoacidic properties of tetraborate ions in molten sodium iodide are stronger... 

V.L. Cherginets and V.V. Banik, Potentiometric Investigation of Acidic Properties of Metaphosphate and Tetraborate Ions and Vanadium(V) Oxide in Molten KCl-NaCl Eutectic at 973 K, Rasplavy N6 (1990) 92-96. 

Thompson and Davis have also considered the effects of electronegativity on the B chemical shift of tetraborate ions [BXj . No direct correlation was found between the measured chemical shift and the electronegativity of X although the shift of the tetraiodo-, tetra-bromo- and tetrachloro-borate ions were in the expected order, the shift of the tetrafluoro- and tetra(phenylacetylene)-borates were unusually high. For the boron trihalides, BX3, Good and Ritter had suggested that the B chemical shift was given by—... 

Although this expression was an over simplification of the situation it was nevertheless found to give good estimates of the 7t-bonding in the boron trihalides. The correlation of the chemical shifts of the tetraborate ions is more complicated because of the absence of n-bonding. The observed shifts of the tetraborates could be represented by the expression—... 

Rizzi, G. P. (2007). On the effect of tetraborate ions in the generation of colored products in thermally processed glycine-carbohydrate solutions. Journal of Agricultural and Food Chemistry, 55, 2016-2019. 

With increasing concentration of boric acid (> 0.025 M) the hydration-dissociation — equilibrium is shifted towards free B(OH)3 molecules, which associate progressively. These macromolecules can be regarded as polyborate anions (J4). Some polynuclear species, B303(0H)4, B303(0H)5" and the very stable tetraborate ion, which is the most predominant dinegative ion in sodium borate solutions, have been detected (Fig. 3). 

This study describes two methods to prepare well-ordered adipate-pillared hydrotalcite-like LDHs. One is the ion-exchange method, the other is the coprecipitation method. The former has not been reported before. As to the latter, products with diffuse or amorphous X-ray patterns were previously observed (Drezdzon 1988 Reichle 1985). These organic-pillared LDHs served as precursors and were ion-exchanged with tetraborate ions. The resultant pillared hydrotalcite-like LDHs had fairly good crystallinity. This is ascribed to tetraborate anions being stable under mildly basic conditions. The variables in preparation conditions which might influence the pillared products were examined. The catalytic activity of the pillared material in 2-butanol decomposition reaction was also discussed. 

Tetraborate is the only species, among the polyoxo-anions used as pillars up to now, that can be stable in basic conditions (scheme 2). Since the hydrotalcite layers and tetraborate ions both are stable under basic conditions, pillared LDHs of high crystallinity can be obtained. Moreover, the resultant pillared compounds are relatively thermo-stable because of the similarity in the basic nature between the layer and the pillar. Therefore, we can conclude that a suitable pillaring agent for hydrotalcite-like LDHs is the one stable in mild basic condition (pH s 8-10). 

Tetraborate ions exhibit a similar low affinity toward the stationary phase allowing for the separation of fluoride and short-chain aliphatic carboxylic acids. 

The formation of (II) provides a quite selective spot test for palladium. Gold must be removed prior to the test because it will cause the development of a deep ruby red in the spot plate test and a diffused violet spot on the paper, apparently due to the reduction of the gold ions to the colloidal metal. Interference may also arise from 0s04 , Os+, Ru+, and RuCle ions because they have distinct self-colors. Mercurous ion causes partial interference by the reduction of part of the palladium to the elementary state, but a positive response can still be seen. It is possible to detect I part of palladium in the presence of 200 parts of platinum or 100 parts of rhodium. Less favorable ratios should be avoided because of the color of these salts. No interference is caused by mercuric and iridic chloride, but free ammonia, ammonium ions, stannous, cyanide, thiocyanate, fluoride, oxalate, and tetraborate ions do interfere. Lead, silver, ferrous, ferric, stannic, cobaltous, nickel, cupric, nitrite, sulfate, chloride, and bromide ions do not interfere. 

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