Bismuth hydrolysis

Dragulescu, C., Nimara, A., and Julean, I. (1972a) Contributions to the bismuth hydrolysis study. I. Spectrophotometric and polarographic investigations on bismuth perchlorate hydrolysis. Chem. Anal, 17, 631-640. 

I. (1974) Contributions to the bismuth hydrolysis study. III. Electrometric investigations on bismuthyl perchlorate hydrolysis. Rev. Roum. Chim., 19, 1455-1459. 

Solutions of many antimony and bismuth salts hydrolyse when diluted the cationic species then present will usually form a precipitate with any anion present. Addition of the appropriate acid suppresses the hydrolysis, reverses the reaction and the precipitate dissolves. This reaction indicates the presence of a bismuth or an antimony salt. 

Bismuth Salts. Bismuth trioxide dissolves in concentrated solutions of strong oxyacids to yield bismuth salts. In more dilute solutions of strong acids or in solutions of weak acids, the oxide reacts to form bismuthyl or basic salts. The normal salts are very susceptible to hydrolysis. 

Bismuth subnitrate [1304-85-4] (basic bismuth nitrate) can be prepared by the partial hydrolysis of the normal nitrate with boiling water. It has been used as an antacid and in combination with iodoform as a wound dressing (183). Taken internally, the subnitrate may cause fatal nitrite poisoning because of the reduction of the nitrate ion by intestinal bacteria. 

Aqueous ceric solutions are widely used as oxidants in quantitative analysis they can be prepared by the oxidation of Ce ( cerous ) solutions with strong oxidizing agents such as peroxodisulfate, S20g ", or bismuthate, BiOg". Complexation and hydrolysis combine to render (Ce" +/Ce +) markedly dependent on anion and acid concentration. In relatively strong perchloric acid the aquo ion is present but in other acids coordination of the anion is likely. Also, if the pH is increased, hydrolysis to... 

Determination of copper as copper(I) thiocyanate Discussion. This is an excellent method, since most thiocyanates of other metals are soluble. Separation may thus be effected from bismuth, cadmium, arsenic, antimony, tin, iron, nickel, cobalt, manganese, and zinc. The addition of 2-3 g of tartaric acid is desirable for the prevention of hydrolysis when bismuth, antimony, or tin is present. Excessive amounts of ammonium salts or of the thiocyanate precipitant should be absent, as should also oxidising agents the solution should only be slightly acidic, since the solubility of the precipitate increases with decreasing pH. Lead, mercury, the precious metals, selenium, and tellurium interfere and contaminate the precipitate. 

The carbonyl group can be deprotected by acid-catalyzed hydrolysis by the general mechanism for acetal hydrolysis (see Part A, Section 7.1). A number of Lewis acids have also been used to remove acetal protective groups. Hydrolysis is promoted by LiBF4 in acetonitrile.249 Bismuth triflate promotes hydrolysis of dimethoxy, diethoxy, and dioxolane acetals.250 The dimethyl and diethyl acetals are cleaved by 0.1-1.0 mol % of catalyst in aqueous THF at room temperature, whereas dioxolanes require reflux. Bismuth nitrate also catalyzes acetal hydrolysis.251... 

In order to estimate% conversion, precipitate was filtered, washed with C2H5OH and dried at 60°C before weighed. Different amounts of bismuth precipitated in solutions of bismuth nitrate, Bi(N03)3, of the concentration 0.071-0.111 M between the pH range 0.9-0.5 respectively, were estimated gravimetrically and given in the Table 9.16. These Bi3+ solutions were sonicated above autohy-drolytic concentration and pH. Hydrolysis began in the form of precipitate due to the formation of BiO(N03). At lower concentration [0.071 M of Bi(N03)3], precipitation started immediately upon sonication, whereas, the time for the appearance of turbidity increased as the concentration increased to 0.111 M. This was perhaps because of the availability of more water molecules for interaction with Bi3+ ions in dilute solutions. Ultrasonically induced hydrolysis was therefore... 

The amount of precipitated bismuth decreased as the concentration of bismuth salt increased (Table 9.16) and the duration of sonication required to bring about hydrolysis also increased. The initial reaction was spontaneous as per Eq. (9.111), which, however, seemed to be facilitated by ultrasonic cavitation at high concentration of bismuth. Since the H+ ions were also produced during the formation of bismuthyl ion, at the point where the sum of concentration of H+ ions present initially and formed by Eq. (9.110) was equal to the concentration required to shift the equilibrium of Eq. (9.111) towards left side, the hydrolysis did not occur even after sonication. 

Another similarity between antimony and bismuth, in the hydrolysis behaviour upon sonication, was that the hydrolysis due to sonication did not begin as long as... 

We have previously reported that when the rearrangement of trans-stilbene oxide was carried out with CF3SO3H, the solution turned red and the product diphenylacetaldehyde was less pure than that obtained with bismuth triflate. This observation points to the role of bismuth(III) triflate as a Lewis acid in the rearrangement of epoxides and not to protic acid catalysis by triflic acid released by hydrolysis of bismuth triflate. 

Bismuth hydroxide is used as an absorbent and in the hydrolysis of ribonucleic acid. It also is used in the isolation of plutonium from irradiated uranium. 

Bismuth oxynitrate is prepared by hydrolysis of bismuth nitrate using either water or sodium bicarbonate solution under mild heating (between 30 to 70°C) and stirring. The composition of the product formed can vary depending on the strength of nitric acid and the quantity of water used. 

Powders containing bismuth compounds have long been used for decorative purposes to generate a shiny luster or lustrous colors (e.g., facial cosmetic powder in ancient Egypt, imitation pearls made by coating glass and ceramic beads). Bismuth oxychloride [7787-59-9], BiOCl, Mr 260.4, was the first synthetic nontoxic nacreous pigment. It is produced by hydrolysis of acidic bismuth solutions in the presence of chloride ions. Precipitation conditions may be varied (concentration, temperature,... 

Bismuth trihalides exhibit an increased tendency toward hydrolysis, usually forming bismuthyl compounds, also called bismuth oxyhalides,... 

Hydrolysis and ammonolysis.—The hydrolysis of salts has previously been described. Bismuth chloride hydrolyzes in a series of stages which can be symbolized ... 

Although the metal-oxygen distances in the hydrolysis complexes are usually too weak and too irregular to give distinct features to a diffraction curve they can be observed and can sometimes be used to choose between different conceivable models for the structure. In hydrolyzed bismuth(III) solutions a dominant complex containing six Bi atoms has been shown to occur (201-204, 226,228). The octahedral arrangement of the six Bi atoms can easily be proved from the diffrac-... 

Bismuth is the most strongly metallic element of the fifth group, yet its salts in aqueous solution undergo partial hydrolysis very readily. In presence of a considerable amount of free acid, the Bi+++ ion is capable of existence in solution but with decreasing quantities of acid the tendency to hydrolyze increases, and the basic salt of bismuth, which is only slightly soluble, separates ... 

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