Stannic, stannous

This low value of the equilibrium constant means that when equilibrium is attained in the ferrous-ferric and stannous-stannic mixture, the concentrations (activities) of ferric and stannous ions must be negligibly small in comparison with those of the ferrous and stannic ions. In other words, when these two systems are mixed, reaction occurs so that the ferric ions are virtually completely reduced to ferrous ions while the stannous are oxidized to stannic ions. This fact is utilized in analytical work for the reduction of ferric to ferrous ions prior to the estimation of the latter by means of dichromate. 

If the halonium ion mechanism is correct and the hydroxyl group is reversibly protonated by the acidic medium, then the rate of formation of the olefin should follow the acidity function //r (formation of carbonium ions from carbinols ). Elimination from the iodo-hydrin of t/ ni-3,4-epoxyoctane was completely non-stereospecific with zinc but gave 75-80% of irans-3-octene with chromous chloride and showed complete fl r/-stereospecificity with stannous chloride . The change in stereospecificity with the variation in the metal cation is interesting. It is tempting to point out the difference in the valence states between chromous-chromic and stannous-stannic of one and two, respectively, as being... 

The net Fceii = 1 -74 V — 0.13V = - -1.61V. The emf (A) of the half-cell is given by the Nernst equation for a stannous/stannic half-cell, with the stannous ion oxidizing to stannic ion ... 

What oxidation states do the following names refer to ferrous, cuprous, mercurous, stannous, stannic, mercuric, cupric, ferric ... 

Both aliphatic and aromatic nitro-compounds can be readily reduced in acid solution to the corresponding primary amine. Thus when a mixture of nitrobenzene and tin is treated with hydrochloric acid, the tin dissolves to give stannous chloride, SnCh, which in these circumstances then reacts with more acid to give stannic chloride, SnCl, and the nascent hydrogen produced from... 

Stannic and stannous, see under Tin Stibine, see Antimony hydride Stibnite, see Antimony(III) sulflde Stolzite, see Lead tungstate(VI)(2—)... 

In some cases, particularly with iaactive metals, electrolytic cells are the primary method of manufacture of the fluoroborate solution. The manufacture of Sn, Pb, Cu, and Ni fluoroborates by electrolytic dissolution (87,88) is patented. A typical cell for continous production consists of a polyethylene-lined tank with tin anodes at the bottom and a mercury pool (ia a porous basket) cathode near the top (88). Pluoroboric acid is added to the cell and electrolysis is begun. As tin fluoroborate is generated, differences ia specific gravity cause the product to layer at the bottom of the cell. When the desired concentration is reached ia this layer, the heavy solution is drawn from the bottom and fresh HBP is added to the top of the cell continuously. The direct reaction of tin with HBP is slow but can be accelerated by passiag air or oxygen through the solution (89). The stannic fluoroborate is reduced by reaction with mossy tin under an iaert atmosphere. In earlier procedures, HBP reacted with hydrated stannous oxide. 

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. 

The pH of a freshly prepared 0.4% solution of stannous fluoride is between 2.8 and 3.5. Initially clear aqueous solutions become cloudy on standing owing to hydrolysis and oxidation. The insoluble residue is a mixture containing stannous and stannic species, fluoride, oxide, oxyfluorides, and hydrates. 

Of the large volume of tin compounds reported in the Hterature, possibly only ca 100 are commercially important. The most commercially significant inorganic compounds include stannic chloride, stannic oxide, potassium staimate, sodium staimate, staimous chloride, stannous fluoride, stannous fluoroborate, stannous oxide, stannous pyrophosphate, stannous sulfate, stannous 2-ethyUiexanoate, and stannous oxalate. Also important are organotins of the dimethyl tin, dibutyltin, tributyltin, dioctyltin, triphenyl tin, and tricyclohexyltin families. 

Stannic and stannous chloride are best prepared by the reaction of chlorine with tin metal. Stannous salts are generally prepared by double decomposition reactions of stannous chloride, stannous oxide, or stannous hydroxide with the appropriate reagents. MetaUic stannates are prepared either by direct double decomposition or by fusion of stannic oxide with the desired metal hydroxide or carbonate. Approximately 80% of inorganic tin chemicals consumption is accounted for by tin chlorides and tin oxides. 

Halides. The tin haUdes of the greatest commercial importance are stannous chloride, stannic chloride, and stannous fluoride. Tin hahdes of less commercial importance are stannic bromide [7789-67-5], stannic iodide [7790-47-8], stannous bromide [10031-24-0], and stannous iodide [10294-70-9] ( ) ... 

Anhydrous stannous chloride, a water-soluble white soHd, is the most economical source of stannous tin and is especially important in redox and plating reactions. Preparation of the anhydrous salt may be by direct reaction of chlorine and molten tin, heating tin in hydrogen chloride gas, or reducing stannic chloride solution with tin metal, followed by dehydration. It is soluble in a number of organic solvents (g/100 g solvent at 23°C) acetone 42.7, ethyl alcohol 54.4, methyl isobutyl carbinol 10.45, isopropyl alcohol 9.61, methyl ethyl ketone 9.43 isoamyl acetate 3.76, diethyl ether 0.49, and mineral spirits 0.03 it is insoluble in petroleum naphtha and xylene (2). 

Stannous Chloride Dihydrate. A white crystalline soHd, stannous chloride dihydrate is prepared either by treatment of granulated tin with hydrochloric acid followed by evaporation and crystallisation or by reduction of a stannic chloride solution with a cathode or tin metal followed by crystallisation. It is soluble in methanol, ethyl acetate, glacial acetic acid, sodium hydroxide solution, and dilute or concentrated hydrochloric acid. It is soluble in less than its own weight of water, but with much water it forms an insoluble basic salt. 

Stannic chloride is made by the direct chlorination of tin at 110—115°C. Any stannous chloride formed in the process is separated from the stannic chloride by volatilization and subsequently chlorinated to stannic chloride. The latter is inert to steel in the absence of moisture and is shipped in plain steel dmms of special design. Because prolonged contact with the skin causes bums, goggles and protective clothing should be used in the handling of stannic chloride. Stannic chloride, like stannous chloride, also forms many complexes (3). 

Other studies of the toxicity of stannous fluoride, sodium pentafluorostannite, sodium pentachlorostannite, sodium chlorostannate, stannous sulfide [1314-95-0] stannous and stannic oxides, stannous pyrophosphate [15578-26 ] stannous tartrate [815-85-0] and other inorganic tin compounds are reviewed in References (dh—12. The OSHA TLV standard for inorganic tin compounds is two milligrams of inorganic tin compounds as tin per cubic meter of air averaged over an eight-hour work shift (47). 

SiHcon tetrabromide [7789-66A], SiBr, and tribromosilane [7789-57-3], SiHBr, are used in a process to make high purity siHcon (40). Stannous bromide [10031 -24-0], SnBr2, is claimed as a catalyst in preparing a lubricant antioxidant (41). Stannic bromide [7789-67-5], SnBr, is used in the metallurgical separation of minerals (42). 

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. 

Rhodan-verbindtmg, /. thiocyanogen compound. -wasserstoff, m. hydrogen thiocyanate, thiocyanic acid, -wasserstoffskure, /. thiocyanic acid, (formerly) sulfocyanic acid, -zlnn, -zinnozyd, n. stannic thiocyanate, tinilV) thiocyanate, -zinnoiydul, n. stannous thiocyanate, tin (II) thiocyanate. 

Zinn-bromwasserstoffsaure, /. bromostannic acid, -butter, /. (Old Chem.) butter of tin (stannic chloride), -charge, /. (Textiles) tin weighting, -chlorammonium, n. ammonium chlorostannate, (Dyeing) pink salt, -chlorid, n. tin chloride, specif, stannic chloride, tin (IV) chloride, -chloriir, n. stannous chloride, tin(II) chloride. 

Zinn-hUtte,/. tin smeltery, tin works, -hydrat, n. tin hydroxide, -hydroxyd, n. tin hydroxide, specif, stannic hydroxide, tin(IV) hydroxide, -hydroxydul, n. stannous hydroxide, tin(II) hydroxide, -jodid, n. tin... 

Stannic, or tin(IV), thiocyanate. -Bulfiir, n. stannous sulfide, tin(II) sulfide, -verbin-dung, /. tin compound, -weiss, n, tin white. -woUe, /. mossy tin,... 

Sodium i-nitro-2-naphtholate, 13, 78 Sodium perbenzoate, 13, 86 Sodium succinate, 12, 72 Sodium sulfide, 12, 68, 76 16, 72 Soxhlet extractor, 16, 69 17, 74 Stannic chloride, 18,1 Stannous chloride, 17, 10, 11 Steam distillation, rapid, 17, 20 Stilbene, 17, 90... 

Tin Nitrate. Stannic nitrate, Sn(N03)4, has been reported, but its existence is questionable. A soln contg stannic tin (Sn4+) can be made by dissolving Sn in nitric acid. It decomps on aging, heating or dilution. The existence of stannous nitrate, Sn(N03)2, must also be questioned. A soln of stannous tin (Sn +) in nitric acid can be made which must be kept cold. It is unstable to heat, dilution and aging (Ref 3)... 

Instead of copper one can use zinc, iron, stannous chloride, or cuprous chloride, the last-named two being oxidized to stannic and cupric chloride respectively. The reactions are carried out at low temperature ( — 10 to — 20°C) in acetone or ethyl acetate (Nesmeyanov et al., 1934 a). 

Sodium aluminium sulphate Sodium bisulphate Sodium hypochlorite Sodium perchlorate Sodium thiocyanate Stannic ammonium chloride Stannic chloride Stannous chloride Uranyl nitrate Zinc chloride Zinc fluorosilicate... 

Owens C, Pytlewski LL, Mikulski CM, et al. 1979. X-ray crystallographic, morphological and thermal-decomposition studies of 2-1 adduces of diisopropyl methylphosphonate with stannous and stannic halides. Journal of Inorganic Nuclear Chemistry 41(9) 1261-1268. 

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