Antimony/ions/salts

Antimony pyrogallate, Sb(C6H503). Antimony(III) salts in the presence of tartrate ions may be quantitatively predpitated with a large excess of aqueous pyrogallol as the dense antimony pyrogallate. The method fadlitates a simple separation from arsenic the latter element may be determined in the filtrate from the predpitation of antimony by direct treatment with hydrogen sulphide. 

The amounts of SbOCl precipitated upon sonication of 30 min duration are given in Table 9.17. The hydrolysis of the salt took place at low pH (less thanl.0) as well. Solutions of all concentrations were sonicated for a period of 30 min. The rate of ultrasonically induced hydrolysis was found to be inversely proportional to the concentration in the solution and seemed to have been confirmed by observing the delay in the appearance of turbidity along with increasing concentration. This was possibly because at lower concentration more water molecules were available for interaction, resulting in the subsequent hydrolysis of antimony ion. 

The role of excess antimony pentafluoride can best be explained by assuming that it is capable of solvating the alkylcarbonium ion salt through interaction of the unshared electron pairs of fluorine with the vacant p-orbital of the sp -hybridized planar central carbon atom of the carbonium ion. In the system of low dielectric constant the alkylcarbonium ion is present not in the free form, but as a tightly bound ion-pair solvation affects this species rather than the free ion. 

For those redox couples that involve a metal ion plus the metal, the logical electrode system is the metal itself. In other words, if the measured quantity is to be cupric ion [copper(II)], a practical indicator electrode is a piece of copper metal. All second-class electrodes involve an active metal in combination with an insoluble compound or salt. Thus, the silver/silver chloride electrode actually is a silver/silver ion electrode system that incorporates the means to control the silver ion concentration through the chloride ion concentration [Eq. (2.14)]. A related form of this is the antimony electrode, which involves antimony and its oxide (an adherent film on the surface of the antimony-metal electrode) such that the activity of antimony ion is controlled by... 

Phosphomolybdic acid reagent (H3[PMol2O4.0]) molybdenum blue is produced by antimony(III) salts. Of the ions in Group II, only tin(II) interferes with the test. The test solution may consist of the filtered solution obtained by treating the Group IIB precipitate with hydrochloric acid the antimony is present as.Sb3+ and the tin as Sn4+, which has no effect upon the reagent. 

Antimony trioxide, Sb O, is amphoteric. In addition to reacting with bases to form antimonites, it reacts with acids to form antimony salts, such as. antimony sulfate, Sb2(S04)3. The antimony ion Sb+ + + hydrolyzes readily to form the antimony I ion SbO. ... 

George A. Olah and Joachim Lukas, Stable carbonium ions. XXXIX. Formation of alkylcarbonium ions via hydride ion abstraction from alkanes in fluorosulfonic acid-antimony pentafluoride solutions. Isolation of some crystalline alkylcarbonium ion salts, /. Am. Chem. Soc. 89, 2227-28 (1967). 

The + 5 acid is known in solution and antimonates(V) can be obtained by dissolving antimony(V) oxide in alkalis. These salts contain the hexahydroxoantimonate(V) ion, [Sb(OH)(,] . 

Antimony forms both a trifluoride and a pentafluoride. It also forms the very stable hexafluoroantimonate ion [17111-95-4] SbF present in solution and a number of salts. 

Antimony trioxide is insoluble in organic solvents and only very slightly soluble in water. The compound does form a number of hydrates of indefinite composition which are related to the hypothetical antimonic(III) acid (antimonous acid). In acidic solution antimony trioxide dissolves to form a complex series of polyantimonic(III) acids freshly precipitated antimony trioxide dissolves in strongly basic solutions with the formation of the antimonate ion [29872-00-2] Sb(OH) , as well as more complex species. Addition of suitable metal ions to these solutions permits formation of salts. Other derivatives are made by heating antimony trioxide with appropriate metal oxides or carbonates. 

Na[Sb(OH)g], respectively. The latter compound is one of the least soluble sodium salts known and is useful in sodium analysis. Numerous polyantimonate(V) derivatives are prepared by heat treatment of mixtures of antimony trioxide and other metal oxides or carbonates. Of these, K Sb O [12056-59-6] and K Sb O [52015-49-3] have been characterized by x-ray. These consist of three-dimensional networks of SbO in which corners and edges are shared with K" ions located in tunnels through the network (23). Simple species such as SbO and Sb20 2, analogous to orthophosphate and pyrophosphate, apparendy do not exist. 

Derivatives of Antimony Pentabromide and Pentaiodide. The existence of SbBr and Sbl is in doubt, although from time to time they are reported in the Hterature (35). The existence of a 1 1 adduct, SbBr 0(0244 )2, however, is generally accepted. In addition, the SbBr ion is known, and from x-ray studies has been found to have a slightly distorted octahedral stmcture (36). Indeed, there are quite a number of complex bromoantimony compounds with alkali metals and organic bases, some of wliich contain Sb(V). Thus the quinuclidinium salt (C24423N44)4Sb2Br2g is actually made up of... 

Amorphous Sb2S2 can be prepared by treating an SbQ solution with 442S or with sodium tliiosulfate, or by heating metallic antimony or antimony trioxide with sulfur. Antimony trisulfide is almost iasoluble ia water but dissolves ia concentrated hydrochloric acid or ia excess caustic. In the absence of air, Sb2S2 dissolves ia alkaline sulfide solutions to form the tliioantimonate(III) ion [43049-98-5], SbS 2, in the presence of air the tetratliioantimonate(V) ion [17638-29-8], SbS , is formed. The lemon-yellow crystalline salt, Na SbS 94420, known as Schhppe s salt [1317-86-8], contains the tetrahedral tetratliioantimonate(V) ion. 

The reaction of toluene-3,4-dithiol(3,4-dimercaptotoluene) and antimony trichloride ia acetone yields a yeUow soHd Sb2(tdt)2, where tdt is the toluene-3,4-dithiolate anionic ligand (51). With the disodium salt of maleonitnledithiol ((Z)-dimercapto-2-butenedinitrile), antimony trichloride gives the complex ion [Sb(mnt)2] , where mat is the maleonitnledithiolate anionic ligand. This complex has been isolated as a yeUow, crystalline, tetraethyl ammonium salt. The stmctures of these antimony dithiolate complexes have apparendy not been unambiguously determiaed. 

Determination of silver as chloride Discussion. The theory of the process is given under Chloride (Section 11.57). Lead, copper(I), palladium)II), mercury)I), and thallium)I) ions interfere, as do cyanides and thiosulphates. If a mercury(I) [or copper(I) or thallium(I)] salt is present, it must be oxidised with concentrated nitric acid before the precipitation of silver this process also destroys cyanides and thiosulphates. If lead is present, the solution must be diluted so that it contains not more than 0.25 g of the substance in 200 mL, and the hydrochloric acid must be added very slowly. Compounds of bismuth and antimony that hydrolyse in the dilute acid medium used for the complete precipitation of silver must be absent. For possible errors in the weight of silver chloride due to the action of light, see Section 11.57. 

In order to establish the identity of the trimethylcarbonium ion, the t-butyl fluoride-antimony pentafluoride system was investigated. It was found that when the vapour of t-butyl fluoride was passed over the surface of purifled liquid antimony pentafluoride (with exclusion of moisture and oxygen) a stable complex layer is formed on the top of the antimony pentafluoride. When this layer was separated and its proton magnetic resonance investigated (see subsequent discussion) the spectrum was found to be identical with that of the least-shielded species formed by decarbonylation of the t-butyloxocarbonium salt... 

The infra-red spectra of the trimethyl, dimethyl- and dimethylethyl-carbonium salts in excess antimony pentaduoride are shown in Figs. 4a, b, and c. The IRTRAN cells used are not transparent below 770 cm , thus obscuring the 650 cm SblY absorption which would, however, be overlapped by the solvent SbFs absorption. The broad, intense absorption band which appears in all the spectra near 1550 cm is present in the solvent spectrum. It was found to be dependent on the purity of the SbFs, but the nature of the impurity was not established. It should also be mentioned that Deno found an intense absorption at 1533 cm in cyclohexenyl cations thus, secondary carbonium ions formed from the reaction with olefins (which arise from deprotonation) could add to this broad absorption. 

Since N-nitrosoimmonium ions seem to be involved in the hydrolysis of a-acetates, it should be possible to isolate such species as stable salts. For this purpose, we selected a system such as XVII in which the phenyl group should provide further stabilization of such a carbonium ion. After the reaction of nitrosyl chloride with the corresponding imines, addition of antimony pentachloride resulted in the precipitation of pale yellow solids these could be isolated and stored under nitrogen for several days at room temperature. ... 

Cationic mechanisms are much more characteristic of the polymerization of oxygen heterocycles, both ethers and acetals. A wide variety of catalysts has been used, including protonic acids, such Lewis acids as boron trifluoride, phosphorus pentafluoride, stannic chloride, antimony pentachloride, titanium tetrachloride, zinc chloride, and ferric chloride, and salts of carbocations or tri-alkyloxonium ions having anions derived from Lewis acids. Some complex, coordination catalysts that appear to operate by a mechanism... 

The action of strong aprotic Lewis acids (antimony(V) fluoride, arsenic(V) fluoride etc.) provokes the ionization of xenon difluoride, leading to the formation of fluoroxenonium salts XcF + MFn or Xe2F3 MFn less strong acceptors of the fluoride ion (hydrogen fluoride, boron trifluoride, etc.) polarize the xenon difluoride molecule. 

Antimony pentaehloride forms the hexaehloroantimonate (V) ion with concentrated solutions of chlorides yielding numerous stable double salts (RCl SbClB or RSbCl ) especially if the cation is large. 

Several studies have been made of the effect of added metal ions on the pinacol/alcohol ratio. Addition of antimony(m) chloride in catalytic amounts changes the product of the electrochemical reduction of acetophenone in acidic alcohol at a lead electrode from the pinacol in the absence of added metal salt to the secondary alcohol in its presence53. Antimony metal was suspected to be an intermediate in the reduction. Conversely, addition of Sm(in) chloride to DMF solutions of aromatic aldehydes and ketones54 and manganese(II) chloride to DMF solutions of hindered aromatic ketones55 results in selective formation of pinacols in excellent yields. When considering these results one should keep in mind the fact that aromatic ketones tend to form pinacols in DMF even in the absence of added metal ions1,29,45. 

Typical alkylation reactions are those of propane, isobutane, and n-butane by the ferf-butyl or sw-butyl ion. These systems are somewhat interconvertible by competing hydride transfer and rearrangement of the carbenium ions. The reactions were carried out using alkyl carbenium ion hexafluoroantimonate salts prepared from the corresponding halides and antimony pentafluoride in sulfuryl chloride fluoride solution and treating them in the same solvent with alkanes. The reagents were mixed at —78°C warmed up to — 20°C and quenched with ice water before analysis. The intermolecular hydride transfer between tertiary and secondary carbenium ions and alkanes is generally much faster than the alkylation reaction. Consequently, the alkylation products are also those derived from the new alkanes and carbenium ions formed in the hydride transfer reaction. 

The first cyclopentadienyl n complexes of phosphorus, arsenic, and antimony have been characterized only recently. The salt-like species LXXXV-LXXXVII containing a cationic n complex are prepared via halide ion abstraction from pentamethylcyclopentadienyl element halides according to Eq. (47) (248-250). 

The sulpho-salts of arsenic, antimony, and stannic tin are particularly characteristic of these metals. (See Preparation 43 and Experiment 11, page 294.) They are easily produced, and all are soluble. They are stable in neutral or basic solutions, but are decomposed by acids, because the anions of the salts combine with hydrogen ions to produce the very weak sulpho-acids, which, being unstable, decompose at once into the sulphides of the metals and hydrogen sulphide ... 

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