SnCl2 STANNOUS CHLORIDE

Tin(ll) chloride, SnCl2, stannous chloride. M.p. 247 - C. While solid (Sn plus gaseous HCl), forms hydrates (SnCl2,2H20 is tin salt) from Sn and aqueous HCl. Acts as acceptor in complexes and forms complexes with transition metals. Used as a mordant. 

Anhydrous stannous chloride. Crystalline stannous chloride, SnCl2.2HjO, is heated for one hour in an oil bath at 195-200°, the cooled melt is powdered, and kept in a desiccator or in a tightly stoppered bottle. 

Stannous Chloride. Stannous chloride is available in two forms anhydrous stannous chloride, SnCl2, and stannous chloride dihydrate [10025-69-1], SnCl2 2H20, also called tin crystals or tin salts. These forms are sometimes used interchangeably however, where stabiUty, concentration, and adaptabihty are important, anhydrous stannous chloride is preferred. Even after long storage, changes in the stannous tin content of anhydrous stannous chloride are extremely low. Physical properties of the tin chlorides are Hsted in Table 1. 

If stannous chloride (SnCl2 2H20) is added, it preferentially reduces the ferric ion to ferrous ion. Two pounds of stannous chloride will reduce 1 pound of ferric ion ... 

The allylation of aldehydes can be carried out using stannous chloride and catalytic cupric chloride or copper in aqueous media." In-situ probing provides indirect (NMR, CV) and direct (MS) evidence for the copper(I)-catalyzed formation of an allyltrihalostannane intermediate in very high concentration in water (Scheme 8.6). Hydrophilic palladium complex also efficiently catalyzes the allylation of carbonyl compounds with allyl chlorides or allyl alcohols with SnCl2 under aqueous-organic... 

Stannous chloride, SnCl2 2H20—0.5TV 56 g per liter. The water should be acid with HC1 and some metallic tin should be kept in the bottle. 

Stannous chloride, SnCl2, is the major ingredient in acid electrotinning electrolyte and is an intermediate for tin chemicals. 

Diammino-stannous Chloride, [Sn(NH3)2]Cl2.—If dry ammonia gas is passed over anhydrous stannous chloride, immersed in a freezing mixture, a yellow powder is formed of composition SnCl2.2NH3. It blackens on exposure to light, and moist air attacks the substance, with formation of stannous oxide and ammonium chloride. If absorption is allowed to take place at ordinary temperature a mixture of mon-ammino-stannous chloride, [Sn(NH3)]Cl2, and diammino-stannous chloride, [Sn(NH3)2]Cl2, is obtained whilst at 100° C. stannous chloride is claimed to absorb ammonia gas, with formation of a white powder of composition corresponding to monammino-stannous chloride, [Sn(NH3)]Cl 2. 

At temperatures between 120° and 300° C. a brownish-red crystalline substance, of composition 3SnCl2.2NH3, is formed. This is the most stable of the compounds, and is only slowly decomposed by water.2, 3 On examination of the temperature of dissociation of the addition products of stannous chloride and ammonia, the highest ammine obtained has composition SnCl2.9NH3 this is formed by the action of liquid ammonia on anhydrous stannous chloride at —78° C. The chloride increases greatly in volume during addition, and the temperature, at which the dissociation pressure is 100 mm., is —55° C. This compound and tetrammino-stannous chloride, [Sn(NH3)4]Cl2, with temperature — 15° C., at which the dissociation pressure is 100 mm., are the only ammines of stannous chloride and ammonia which exist with certainty.4... 

A chemically pure grade of stannous chloride (SnCl2-2H20) should be used. Lower yields are obtained with technical stannous chloride. 

Anhydrous Stannous Chloride.—Stannous chloride (SnCl2,2H20) (1 mol.) is treated with acetic anhydride (2 mols.). Dehydration is almost instantaneous, much heat is evolved and the anhydrous salt separates. When collected, and washed free of acetic acid with dry ether, it does not appear to be hygroscopic, and may be preserved indefinitely in a desiccator. It is readily soluble in acetone and in anhydrous methyl or ethyl alcohol insoluble in benzene or chloroform and it may be crystallised from acetic acid containing a little acetic anhydride. (For uses see p. 238 and J. C. S 1931, 82.)... 

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