Tin IV

The reagent is prepared by dissolving 0-2 g 4-methyl-l, 2-dimercapto-benzene in 100 ml 1 per cent sodium hydroxide solution and adding 0-3-0-5 g thio-glycollic acid. The use of the latter in the reagent is not imperative, but it serves to facilitate the reduction of any tin(IV) ions present. The reagent is discarded if a white precipitate of the disulphide forms. 

Reactions of tin(lV) ions To study these reactions use a 0-25m solution of ammonium hexachlorostannate(IV) by dissolving 92 g (NH4)2[SnCl6] in 250 ml concentrated hydrochloric acid and diluting the solution to 1 litre with water. 

Hydrogen sulphide yellow precipitate of tin(IV) sulphide SnS2 from dilute acid solutions (0 3m). The precipitate is soluble in concentrated hydrochloric acid (distinction from arsenic(III) and mercury(II) sulphides), in solutions of alkali hydroxides, and also in ammonium sulphide and ammonium polysulphide. Yellow tin(IV) sulphide is precipitated upon acidification. 

No precipitation of tin(IV) sulphide occurs in the presence of oxalic acid, due to the formation of the stable complex ion of the type [Sn(C204)4(H20)2]4 this forms the basis of a method of separation of antimony and tin. 

Sodium hydroxide solution gelatinous white precipitate of tin(IV) hydroxide Sn(OH)4, soluble in excess of the precipitant forming hexahydroxostannate(IV) 

The solubility and thermodynamic properties of cassiterite, Sn02(s), have been thoroughly reviewed by Gamsjager et al. (2012). From the collection of data that was available, the following thermodynamic data were selected  

The solubility of both crystalline and amorphous SnOjls) is constant from low pH up to a pH of about 8 (Gamsjager et al., 2012). For the amorphous oxide, the equilibrium tin(I V) concentration is marginally greater than 6 x 10 mol kg whereas for the crystalline oxide it is lower at 9 x 10 molkg . In relation to the 

On the basis of this latter value, it would appear that the lower monomeric tin(IV) species could not occur, thus the stability constant data given for the species SnOH to Sn(OH)3 by Nazarenko, Antonovich and Nevskaya (1971) are not accepted. The stability constant for Sn(OH)4(aq) would appear to be not inconsistent with that derived for the first hydrolysis constant of tin(lV) by Brown and Wanner (1987) (i.e. log = 1.91) which also suggests that it would be extremely difficult to measure at least the first hydrolysis constant, and possibly the second and third, using experimental techniques. Reported stability constants (Kuril chikova and Barsukov, 1970 Vasilev, Glavina and Shorokhova, 1979 House and Kelsall, 1984) for Sn(OH)4(aq) that indicate a much less stable species are therefore also rejected by this review. 

Earlier Barsukov and KHntsova (1970) had also studied the solubility of Sn02(s) in alkaline solutions. The stability constant they obtained for the formation of Sn(OH)5 was more than four orders of magnitude less than that derived by Amaya et al. (1997). Gamsjager et al. (2012) re-evaluated the data they listed in a later paper (Klintsova, Barsukov and Vernadsky, 1973), where the solubility of cassiterite was studied across the temperature range of 25-300 C. In this case, the solubility constant derived by Gamsjager et al. (2012) for Sn(OH)g for 200 C was not consistent with that derived from the data of Amaya et al. (1997) at 25 C. As such Gamsjager et al. rejected the data of both Barsukov and Klintsova (1970) and Klintsova, Barsukov and Vernadsky (1973) as is done also in the present review. 

From the data at zero ionic strength and the accepted stability constant for Sn(OH)4(aq), the following two constants are derived for Sn(OH)5 and Sn(OH)g2-  

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Tin IV) bromide, SnBr4. M.p. 33°C, b.p. 203 C, prepared from the elements. Fonns many complexes, including [SnBr ] ions. 

Tin IV) chloride, SnCU, stannic chloride. M.p. — 33" C, b.p. 1I4°C. Colourless fuming liquid (Sn plus CI2) hydrolysed in water but forms SnCl4,5H20 and [SnCl p" from acid solutions, soluble in organic solvents. Used as a mordant. 

Tin IV) sulphide, SnS2- Precipitated from Sn(IV) solution with H2S or Sn plus S under pressure. NH4CI, Sn, S heated gives a yellow solid (mosaic gold). Used as a pigment. 

Silicon, germanium, tin and lead can make use of unfilled d orbitals to expand their covalency beyond four and each of these elements is able (but only with a few ligands) to increase its covalency to six. Hence silicon in oxidation state -f-4 forms the octahedral hexafluorosilicate complex ion [SiFg] (but not [SiCl] ). Tin and lead in oxidation state -1-4 form the hexahydroxo complex ions, hexahydroxostannate(IV). [Sn(OH) ] and hexahydroxoplum-bate(IV) respectively when excess alkali is added to an aqueous solution containing hydrated tin(IV) and lead(IV) ions. 

Concentrated nitric acid, however, is an oxidising agent and tin reacts to give hydrated tin(IV) oxide in a partly precipitated, partly colloidal form, together with a small amount of tin(II) nitrate, Sn(N03)2 ... 

A similar oxidation reaction occurs with concentrated sulphuric acid but in this case hydrated tin(IV) ions remain in solution ... 

Ordinary white tin is not attaeked by air at ordinary temperatures but on heating in air it forms tin(IV) oxide, Sn02. 

Tin(II) oxide is a dark-coloured powder which oxidises spontaneously in air with the evolution of heat to give tin(IV) oxide, SnO, ... 

Tin(IV) oxide occurs naturally, clearly indicating its high stability. It can be prepared either by heating tin in oxygen or by heating the... 

Tin(IV) oxide is insoluble in water, but if fused with sodium hydroxide and the mass extracted with water, sodium hexahydroxo-stannate(IV) is formed in solution ... 

If a dilute acid is added to this solution, a white gelatinous precipitate of the hydrated tin(IV) oxide is obtained. It was once thought that this was an acid and several formulae were suggested. However, it now seems likely that all these are different forms of the hydrated oxide, the differences arising from differences in particle size and degree of hydration. When some varieties of the hydrated tin(IV) oxide dissolve in hydrochloric acid, this is really a breaking up of the particles to form a colloidal solution—a phenomenon known as peptisation. 

This reaction has been used to recover tin from scrap tinplate.) Tin(IV) chloride is a colourless liquid, which fumes in air due to hydrolysis ... 

Tin(IV) in aqueous acid gives a yellow precipitate with hydrogen sulphide, and no reaction with mercury(II) chloride. 

Give brief experimental details to indicate how you could prepare in the laboratory a sample of either tin(IV) chloride or tin(IV) iodide. How far does the chemistry of the oxides and chlorides of carbon support the statement that the head element of a group in the Periodic Table is not typical of that group (JMB, A)... 

Tin(ll) chloride, in presence of hydrochloric acid, is oxidised to tin(IV) chloride, the nitrate ion in this case being reduced to hydroxylamine and ammonia. 

Chlorine reacts with most elements, both metals and non-metals except carbon, oxygen and nitrogen, forming chlorides. Sometimes the reaction is catalysed by a trace of water (such as in the case of copper and zinc). If the element attacked exhibits several oxidation states, chlorine, like fluorine, forms compounds of high oxidation state, for example iron forms iron(III) chloride and tin forms tin(IV) chloride. Phosphorus, however, forms first the trichloride, PCI3, and (if excess chlorine is present) the pentachloride PCI5. 

With the catalysis of strong Lewis acids, such as tin(IV) chloride, dipyrromethenes may aiso be alkylated. A very successful porphyrin synthesis involves 5-bromo-S -bromomethyl and 5 -unsubstituted 5-methyl-dipyrromethenes. In the first alkylation step a tetrapyrrolic intermediate is formed which cyclizes to produce the porphyrin in DMSO in the presence of pyridine. This reaction sequence is useful for the synthesis of completely unsymmetrical porphyrins (K.M. Smith, 1975). 

Another type of demasking involves formation of new complexes or other compounds that are more stable than the masked species. For example, boric acid is used to demask fluoride complexes of tin(IV) and molybdenum(VI). Formaldehyde is often used to remove the masking action of cyanide ions by converting the masking agent to a nonreacting species through the reaction ... 

Nitryl chloride Ammonia, sulfur trioxide, tin(IV) bromide and iodide... 

The first known fire-retardant process found durable to laundering was developed in 1912 (4). A modification of an earlier process (5), this finish was based on the formation of a tin(IV) oxide [18282-10-5] deposit. Although the fabric resulting from treatment was flame resistant, afterglow was reputed to be a serious problem, resulting in the complete combustion of the treated material through smoldering. 

The main binary tin fluorides are stannous fluoride and stannic fluoride. Because the stannous ion,, is readily oxidized to the stannic ion,, most reported tin and fluorine complexes are of tin(IV) and fluorostannates. Stannous fluoroborates have also been reported. 

Alkyltin Intermedia.tes, For the most part, organotin stabilizers are produced commercially from the respective alkyl tin chloride intermediates. There are several processes used to manufacture these intermediates. The desired ratio of monoalkyl tin trichloride to dialkyltin dichloride is generally achieved by a redistribution reaction involving a second-step reaction with stannic chloride (tin(IV) chloride). By far, the most easily synthesized alkyltin chloride intermediates are the methyltin chlorides because methyl chloride reacts directiy with tin metal in the presence of a catalyst to form dimethyl tin dichloride cleanly in high yields (21). Coaddition of stannic chloride to the reactor leads directiy to almost any desired mixture of mono- and dimethyl tin chloride intermediates ... 

Condensation catalysts include both acids and bases, as well as organic compounds of metals. Both tin(II) and tin(IV) complexes with carboxyhc acids ate extremely useful. It has been suggested that the tin catalyst is converted to its active form by partial hydrolysis followed by reaction with the hydrolyzable silane to yield a tin—sdanolate species (eqs. 22 and 23) (193,194). 

Tin, having valence of +2 and +4, forms staimous (tin(II)) compounds and stannic (tin(IV)) compounds. Tin compounds include inorganic tin(II) and tin(IV) compounds complex stannites, MSnX., and staimates, M2SnX, and coordination complexes, organic tin salts where the tin is not bonded through carbon, and organotin compounds, which contain one-to-four carbon atoms bonded direcdy to tin. 

Stannic Chloride. Stannic chloride is available commercially as anhydrous stannic chloride, SnCl (tin(IV) chloride) stannic chloride pentahydrate, SnCl 5H20 and in proprietary solutions for special appHcations. Anhydrous stannic chloride, a colorless Aiming Hquid, fumes only in moist air, with the subsequent hydrolysis producing finely divided hydrated tin oxide or basic chloride. It is soluble in water, carbon tetrachloride, benzene, toluene, kerosene, gasoline, methanol, and many other organic solvents. With water, it forms a number of hydrates, of which the most important is the pentahydrate. Although stannic chloride is an almost perfect electrical insulator, traces of water make it a weak conductor. 

Stannic Oxide. Stannic oxide tin(IV) oxide, white crystals, mol wt 150.69, mp > 1600° C, sp gr 6.9, is insoluble in water, methanol, or acids but slowly dissolves in hot, concentrated alkaH solutions. In nature, it occurs as the mineral cassiterite. It is prepared industrially by blowing hot air over molten tin, by atomizing tin with high pressure steam and burning the finely divided metal, or by calcination of the hydrated oxide. Other methods of preparation include treating stannic chloride at high temperature with steam, treatment of granular tin at room temperature with nitric acid, or neutralization of stannic chloride with a base. 

The reactivity of five-membered rings with one heteroatom to electrophilic reagents has been quantitatively compared in a variety of substitution reactions. Table 2 shows the rates of substitution compared to thiophene for formylation by phosgene and iV,AT-dimethylfor-mamide, acetylation by acetic anhydride and tin(IV) chloride, and trifluoroacetylation with trifluoroacetic anhydride (71AHC(13)235). 

Section 5.10.3.2). Treatment of methyl 6-phthalimido penicillinate (jR)-sulfoxide (40) with JV-chlorosuccinimide in refluxing carbon tetrachloride gives an epimeric mixture of sulfinyl chlorides (41) which are ring closed to epimeric 3-methylenecepham sulfoxides (42a) using tin(IV) chloride. Reduction with phosphorus tribromide gives the desired methyl 7-phthalimido-3-methylenecepham 4-carboxylate (42b). 

In actual practice, catalysts are usually employed to catalyze the isocyanate/ alcohol reaction at room temperature. Typical catalysts for this reaction are the tin(IV) salts, e.g., dibutytin dilaurate, or tertiary amines, such as triethylene diamine [2]. 

The most common catalyst used in urethane adhesives is a tin(lV) salt, dibutyltin dilaurate. Tin(IV) salts are known to catalyze degradation reactions at high temperatures [30J. Tin(II) salts, such as stannous octoate, are excellent urethane catalysts but can hydrolyze easily in the presence of water and deactivate. More recently, bismuth carboxylates, such as bismuth neodecanoate, have been found to be active urethane catalysts with good selectivity toward the hydroxyl/isocyanate reaction, as opposed to catalyzing the water/isocyanate reaction, which, in turn, could cause foaming in an adhesive bond line [31]. 

Certain metal catalysts, such as tin(IV) salts and tertiary amines, may work synergistically with oxygen to cause oxidative degradation of urethanes [88]. 

The first large-scale use of chlorine was for bleaching paper and cotton textiles it also is widely used as a germicide for public water supplies. Presently it is used principally in production of the chemical compounds sulfur chloride, thionyl chloride, phosgene, aluminum chloride, iron(ni) chloride, titaniura(IV) chloride, tin(IV) chloride, and potassium chlorate. 

Tin(IV) halides are more straightforward. Snp4 (prepared by the action of anhydrous HF on SnCU) is an extremely hygroscopic, white crystalline compound which sublimes above 700°. The structure (unlike that of CF4, SiF4 and GeF4) is polymeric with octahedral coordination... 

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