Hydrous Tin Oxide

Negative uptake of Na and negligible uptake of Cs (radiotracer, 0.001-0.01 M chlorides) is reported in [612]. 

Negligible uptake of the following inert-electrolyte ions has been reported  

Substantial uptake of Cl and moderate uptake of Na was found in [3197], Substantial uptake of the following inert-electrolyte ions has been 

Moderate uptake of Na and Cl (13 different samples) at pH 6.5 was reported in [3199] (point of equal uptake, no independent estimation of PZC). 

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As with other hydrous metal oxides, such as alumina and zirconia, tin oxide is an amphoteric ion exchanger that exhibits cation exchange properties at basic pH. Hydrous tin oxide, however, appears to be particularly favored by virtue of its high Sr(ll) distribution coefficient (Kd Sr-bound/Sr-free) and high separation factor, Kd[Sr(ll)/Rb(l)], over a broad pH range (Table II Figure 1). 

SnO and hydrous tin(II) oxide are amphoteric, dissolving readily in aqueous acids to give Sn" or its complexes, and in alkalis to give the pyramidal Sn(OH)3 at intermediate values of pH, condensed basic oxide-hydroxide species form, e.g. [(OH)2SnOSn(OH)2] and [Sn3(OH)4] +, etc. Analytically, the hydrous oxide frequently has a composition close to 3Sn0.H20 and an X-ray study shows it to... 

Sn02, cassiterite, is the main ore of tin and it crystallizes with a rutile-type structure (p. 961). It is insoluble in water and dilute acids or alkalis but dissolves readily in fused alkali hydroxides to form stannates M Sn(OH)6. Conversely, aqueous solutions of tin(IV) salts hydrolyse to give a white precipitate of hydrous tin(IV) oxide which is readily soluble in both acids and alkalis thereby demonstrating the amphoteric nature of tin(IV). Sn(OH)4 itself is not known, but a reproducible product of empirical formula Sn02.H20 can be obtained by drying the hydrous gel at 110°, and further dehydration... 

Numerous oxoacid salts of Sn and Sn have been reported and several basic salts are also known. Anhydrous Sn(N03)2 has not been prepared but the basic salt Sn3(0H)4(N03)2 can be made by reacting a paste of hydrous tin(II) oxide with aqueous HNO3 the compound may well contain the oligomeric cation [Sn3(OH)4] + illustrated on p. 384, Sn(N03)4 can be obtained in anhydrous reactions of... 

Antimony trioxide, 8-stannic acid (hydrous tin(IV) oxide), zinc hydroxystannate, and zinc stannate were incorporated into the commercial brominated polyester resin at levels of 1,2,5 and 10% by weight. No processing problems were encountered and the samples cured satisfactorily to give rigid, opaque strips. 

Polyacrylic acid Hybrid organic/inorganic network polymers were formed via the reaction of polyacrylic acid with tin(IV). titanium(IV), and silicon (IV) alkoxides and subsequent hydrolysis to form mesoporous materials. Treatment by nitric acid removed the polyacrylate template and produced microporous inorganic hydrous metal oxides Surface areas characterized by BET measurements 130... 

The main species in highly basic solutions is [Sn(OH)6] in less basic solutions [SnOs] " is obtained. Tin(IV) sulfide is soluble in aqueous alkaline media, containing sulfide ion, to give [SnSs] ". All tin(IV) species in aqueous solutions tend to undergo hydrolysis, e g. to hydrous tin(IV) oxide. 

Figure 11 The pH response of tin(IV)antimonate with various compositions during their neutralization with base. a-Sn a-hydrous tin(IV) oxide, A-SbA amorphous antimonic(V) acid, numerical number mol ratio of Sb/Sn, exchanger, 0.25 g total volume, 12.5 cm" temp., 25 C ionic strength, 0.1 M (KOH + KCl). (From M. Abe and T. Ito, Abgyo Kagaku Zassbi, 79 A40 (1967). With permission.)...

Mishra, S.P, Dubey, S.S., and Tiwari, D., Inorganic particulates in removal of heavy metal toxic ions. IX. Rapid and efficient removal of Hg(II) by hydrous manganese and tin oxides, J. Colloid Interf. Sci., 219, 61, 2004. 

Several bivalent tin compounds have appreciable water solubilities, e.g. the solubility of tin(II) chloride is 83.9 g in 100mL at 0°C, that of tin(II) fluoride is 4.1 g in 100 mL at 25 °C, and of tin(II) sulfate is 35.2 g in 100 mL at 10 °C. Aqueous solutions are susceptible to hydrolysis to hydrous tin(II) oxide and oxidation to Sn species the stability of aqueous solutions depends upon the anions present and the pH. The presence of anions that are able to form strong complexes with Sn e.g. F or OAc , enhances resistance to hydrolysis and oxidation. Ease of hydrolysis increases with pH at very high pH, disproportionation of Sn to Sn° and Sn results. 

Justification. Investigation of a number of gelatinous hydrous metal oxides (frequently called hydroxides, although their full structures are uncertain) has established ( ) that hydrous titanium (IV), zirconium (IV), iron (III), vanadium (III) and tin (II) oxides at least are capable of forming with enzymes insoluble complexes which are enzymically active. From the practical viewpoint hydrous titanium (IV) and zirconium (IV) oxides proved the most satisfactory. Comparatively high retentions of enzyme specific activity may be achieved (3, 4, 5). Such hydrous metal oxide materials have also proved to be suitable for the immobilisation of amino acids and peptides ( ), antibiotics with retention of antimicrobial activity ( ), polysaccharides J ), etc. 

Costantino, U., Curini, M., Montanaii, R, Nocchetti, M., Rosati, O. 2008. Hydrotalcite-like compounds as heterogeneous catalysts in liquid phase organic synthesis. II. Preparation of 4H-chromenes promoted by hydrotalcite doped with hydrous tin(IV) oxide. Microporous andMesoporous Materials 107(l-2) 16-22. 

Tin compounds have been known as flame retardants since the midnineteenth century, when processes based on the in situ precipitation of hydrous tin(iv) oxide were developed to impart flame-resist properties to cotton and other cellulosic materials ... 

The s5mthesis of 4H-chromenes 21, from salicylaldehydes and different cyanoacetates, promoted by MgAl-hydro-taldtes doped with hydrous tin(IV) oxide was reported by Costantino et al. (Scheme 13) [76]. The reaction takes place under solvent-free and mild reaction conditions yielding compound 21 witii good yields during prolonged reaction times. 

A basic tin(II) nitrate Sn3(0H)4(N03)2 is made by the action of nitric acid upon a paste of hydrous tin(II) oxide. It is believed to be ionic and to contain the ion SnslOH illustrated in Fig. 6 (a). Basic tin nitrate is partly hydrolysed on dissolution in water. The presence of Sn(II) ions with N03 makes thermal decomposition of the basic nitrate exceedingly violent, and Sn3(0H)4(N03)2 may be classified as a high explosivei . ... 

Tin(IV) sulphate as the dihydrate Sn(S04)2.2H20 is obtained from hydrous tin(IV) oxide in hot dilute sulphuric acid. The colourless crystals are exceptionally hygroscopic and best stored in sealed ampoulesi24. Tin(IV) sulphate hydrolyses completely in water, with precipitation of hydrous tin(IV) oxide, but is nevertheless freely soluble in dilute sulphuric acid to give a clear solution. 

Estimates of activity coefficients suggest that the dissolution of hydrous tin(IV) oxide in dilute sulphuric acid produces the SnS042+ ion in solution, with more concentrated sulphuric acid solutions causing further complexing to form Sn(S04)2 and H2Sn(S04)3 in... 

Purification actually starts with the precipitation of the hydrous oxides of iron, alumina, siUca, and tin which carry along arsenic, antimony, and, to some extent, germanium. Lead and silver sulfates coprecipitate but lead is reintroduced into the electrolyte by anode corrosion, as is aluminum from the cathodes and copper by bus-bar corrosion. 

Acceleration modifies the surface layer of palladium nuclei, and stannous and stannic hydrous oxides and oxychlorides. Any acid or alkaline solution in which excess tin is appreciably soluble and catalytic palladium nuclei become exposed may be used. The activation or acceleration step is needed to remove excess tin from the catalyzed surface, which would inhibit electroless plating. This step also exposes the active palladium sites and removes loose palladium that can destabilize the bath. Accelerators can be any acidic or alkaline solution that solubilizes excess tin. 

The monoxides and dioxides of germanium, tin, and lead are all known. Especially when obtained as precipitates, the oxides contain water and consist of a mixture of the oxide, hydroxide, and hydrous oxide. For example, GeO, GeO-xl l20, and Ge(OH)2 (which could be written as GeOH20) all exist in equilibria or in mixtures. GeO is obtained from the reaction... 

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