Stannous oxide

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. 

Stannous fluoride probably was first prepared by Scheele in 1771 and was described by Gay-Lussac and Thenard in 1809. Commercial production of stannous fluoride is by the reaction of stannous oxide and aqueous hydrofluoric acid, or metallic tin and anhydrous hydrogen fluoride (5,6). Snp2 is also produced by the reaction of tin metal, HP, and a halogen in the presence of a nitrile (7). 

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. 

Solutions of anhydrous stannous chloride are strongly reducing and thus are widely used as reducing agents. Dilute aqueous solutions tend to hydrolyze and oxidize in air, but addition of dilute hydrochloric acid prevents this hydrolysis concentrated solutions resist both hydrolysis and oxidation. Neutralization of tin(II) chloride solutions with caustic causes the precipitation of stannous oxide or its metastable hydrate. Excess addition of caustic causes the formation of stannites. Numerous complex salts of stannous chloride, known as chlorostannites, have been reported (3). They are generally prepared by the evaporation of a solution containing the complexing salts. 

Stannous Oxide. Stannous oxide, SnO ((tin(II) oxide), mol wt 134.70, sp gr 6.5) is a stable, blue-black, crystalline product that decomposes at above 385°C. It is insoluble in water or methanol, but is readily soluble in acids and concentrated alkaHes. It is generally prepared from the precipitation of a stannous oxide hydrate from a solution of stannous chloride with alkaH. Treatment at controUed pH in water near the boiling point converts the hydrate to the oxide. Stannous oxide reacts readily with organic acids and mineral acids, which accounts and for its primary use as an intermediate in the manufacture of other tin compounds. Minor uses of stannous oxide are in the preparation of gold—tin and copper—tin mby glass. 

Stannous Oxide Hydrate. Stannous oxide hydrate [12026-24-3] SnO H2O (sometimes erroneously called stannous hydroxide or stannous acid), mol wt 152.7, is obtained as a white amorphous crystalline product on treatment of stannous chloride solutions with alkaH. It dissolves in alkaH solutions, forming stannites. The stannite solutions, which decompose readily to alkaH-metal stannates and tin, have been used industrially for immersion tinning. 

Stannous Sulfate. Stannous sulfate (tin(Il) sulfate), mol wt 214.75, SnSO, is a white crystalline powder which decomposes above 360°C. Because of internal redox reactions and a residue of acid moisture, the commercial product tends to discolor and degrade at ca 60°C. It is soluble in concentrated sulfuric acid and in water (330 g/L at 25°C). The solubihty in sulfuric acid solutions decreases as the concentration of free sulfuric acid increases. Stannous sulfate can be prepared from the reaction of excess sulfuric acid (specific gravity 1.53) and granulated tin for several days at 100°C until the reaction has ceased. Stannous sulfate is extracted with water and the aqueous solution evaporates in vacuo. Methanol is used to remove excess acid. It is also prepared by reaction of stannous oxide and sulfuric acid and by the direct electrolysis of high grade tin metal in sulfuric acid solutions of moderate strength in cells with anion-exchange membranes (36). 

Staono-. stannous, stanno-, tin(II). -azetat, n. stannous acetate, tin(II) acetate, -chlorid, n. stannous chloride, tin(II) chloride, -chlor-wasserstoffsMure, /. chlorostannous acid, -hydroxyd, n. stannous hydroxide, tin(II) hydroxide. -jodid, n. stannous iodide, tin(II) iodide. -jodwasserstoffsaure, /. iodostannous acid, -oxyd, n. stannous oxide, tin(II) oxide, -salz, n. stannous salt, tin(II) salt, -sulfid, n. stannous sulfide, tin(II) sulfide. -verbindung, /, stannous compoimd, tin(II) compound,... 

When tin is fully exposed out of doors, corrosion is uniform, and the rate falls only slightly with time. The metal becomes dull and accumulates a compact layer of pale grey product, mainly stannous oxide. Rates observed during exposures in the USA for periods of up to 20 years were as follows... 

Stannous fluoride, 24 801, 804, 8 340 Stannous fluoroborate, 24 807 Stannous octanoate, 24 826 Stannous oxalate, 24 827 Stannous oxide, 24 804—805 Stannous oxide hydrate, 24 805 Stannous pyrophosphate, 24 807 Stannous sulfate, 24 806-807 Stannylquinones, 21 254 Stanton number (St), 15 687t Stanylenka 460 HRST, 19 764 Staphylococci, coagulase-negative, 21 216 Staphylococcus aureus... 

Synonyms stannous oxide tin monoxide tin protoxide Uses... 

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. 

A. J. Balard found that stannous oxide is oxidized to stannic oxide, and the latter is not altered by hypochlorous acid chromic oxide is oxidized to chromic acid manganese, nickel, cobalt, and lead oxides are also converted into peroxides by hypochlorous acid bismuth oxide and manganese dioxide are not altered by this acid. 

Special containers have been developed for anesthetic ether to prevent deterioration before use. Their effectiveness as stabilizers usually depends on the presence of a lower oxide of a metal having more than one oxidation state. Thus the sides and the bottoms of tin-plate containers are electroplated with copper, which contains a small amount of cuprous oxide. Stannous oxide is also used in the linings for tin containers. Instead of using special containers, iron wire or certain other metals and alloys or organic compounds have been added to ether to stabilize it. 

B. C. Dutt and S. N. Sen found that when nitric oxide is passed into a suspension of barium dioxide in water, barium nitrite, not nitrate, is formed. P. Sabatier and J. B. Senderens observed no change when nitric oxide is passed over Cuprous Oxide at 500°. H. A. Auden and G. J. Fowler observed that dry nitric oxide and Silver oxide, at ordinary temp., form silver and silver nitrate P. Sabatier and J. B. Senderens also obtained silver and silver nitrite by passing nitric oxide into water with silver oxide in suspension. C. F. Schonbein found gold oxide is reduced by moist nitric oxide, forming nitrous acid. P. Sabatier and J. B. Senderens found that titanium sesquioxide forms white titanic oxide when heated in an atm. of nitric oxide and that stannous oxide below 500° burns in an atm. of nitric oxide, forming stannic oxide. If nitric oxide be passed into water with lead dioxide in suspension, the water is coloured, and in about 3 hrs., lead nitrite and nitrate are formed, and later, rhombic crystals of a basic nitrite. B. C. Dutt and S. N. Sen said that the nitrate is formed by the action of the dioxide on the nitrite. Lead dioxide is reduced to lead oxide by nitric oxide at 315°, and H. A. Auden and G. J. Fowler found that the reaction begins at 15°, when a basic lead nitrite is... 

There are two series of compounds of tin and the halogens those related to stannous oxide, SnO, in which the metal has a valence of 2 (stannous salts), and those related to stannic oxide, Sn02, in which it has a valence of 4 (stannic salts). The compounds with lower valence are usually prepared by the action of the halogen acids on the metal. Stannous chloride, for example, is formed when hydrochloric acid reacts with tin. Stannic salts, on the other hand, are prepared by the reaction of tin and the free halogen. In this preparation stannic bromide results from the reaction of bromine and tin. The reaction between the two ele-... 

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