Metallic tin

It is a colourless gas which decomposes on heating above 420 K to give metallic tin, often deposited as a mirror, and hydrogen. It is a reducing agent and will reduce silver ions to silver and mercury(II) ions to mercury. SnSn bonding is unknown in hydrides but does exist in alkyl and aryl compounds, for example (CH3)3Sn-Sn(CH3)3. 

Stannic chloride is prepared by treating metallic tin with chlorine Sn + 2C1 SnCl4... 

Stannous chloride, SnClj THjO—0.5N 56 g per liter. The water should be acid with HCl and some metallic tin should be kept in the bottle. 

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). 

The facile reaction of metallic tin in the presence of hydrogen chloride with acryUc esters to give high yields of bis( P-alkoxycarbonyleth5l)tin dichlorides is reported in References 115 and 116. This reaction proceeds at atmospheric pressure and room temperature and has been practiced commercially. Halogenostaimanes have been postulated as intermediates (105). 

Figure 4 VEELS and Auger spectra for tiK angles of 0°, 45°, and 60° taken from a tin sample covered by a 0.5-nm oxide layer. The doublet AES peaks are the Sn (410) peaks while the singlet AES peak is the O (510) taken with the same gain. VEELS peaks are oxide related, while the Sn (410) peak is due primarily to the metallic tin beneath the oxide, illustrating the superior depth resolution of VEELS.

An example of a spectrum with a chemical shift is that of the tin 3d peaks in Eig. 2.8. A thin layer of oxide on the metallic tin surface enables photoelectrons from both the underlying metal and the oxide to appear together. Resolution of the doublet 3 ds/2, 3 dii2 into the components from the metal (Sn ) and from the oxide Sn " is shown in Eig. 2.8 B. The shift in this instance is 1.6-1.7 eV. Curve resolution is an operation that can be performed routinely by data processing systems associated with photoelectron spectrometers. 

In cold climates, metallic tin (solid 11) slowly changes to solid 1. (Solid phase transitions are often slow.) The change from a shiny metallic surface to a brittle and llaky grey surface is known as tin disease. 

L.31 A 1.50-g sample of metallic tin was placed in a 26.45-g crucible and heated until all the tin had reacted with the oxygen in air to form an oxide. The crucible and product together were found to weigh 28.35 g. (a) What is the empirical formula of the oxide (b) Write the name of the oxide. 

A requirement for metallic character is that unsynchronized resonance of covalent bonds occur, which means that M and M° have an unoccupied orbital available to accept an additional bond, changing them to M° and M, respectively. M does not need the extra orbital, because it cannot change to M2-. A hyperelectronic metal is one in which the number of outer electrons is greater than the number of outer orbitals, not including the metallic orbital. An example is metallic tin, with 14 outer electrons and 9 outer orbitals (6j, three 6p, five 5d). Sn+ and Sn° have five unshared electron pairs, and Sn has six. Sn+ and Sn form three covalent bonds, and Sn° forms two. Sn+ and Sn° have a metallic orbital, and Sn does not. They may be represented as... 

One approach (.40) has been to conduct the reaction in the presence of a more electropositive metal, often as an alloy. In the presence of magnesium, tin reacts with ethyl bromide to give tetraethyl tin, and various additives promote the reaction, the sequence of effectiveness being carbitols I > tetrahydrofuran, tetrahydrothiophene > ether triethylamine Br the ions ClOj, PFg, BFj, and BPhj are without effect. It is suggested that this reflects the coordination of the additive (L) to the Grignard reagent that is first formed, making it more reactive towards metallic tin. 

Metallic tin reacts with methyl halides and 2-halogenopropanoates at 135°, catalyzed by magnesium and butyl iodide in tetrahydrofuran, to give compounds MeSnXjCHgCHgCOjR, from which various other derivatives were prepared (42). 

The preparation of some polychalcogenide solids can be achieved at 200-450 °C by molten salt (flux) methods. The reaction of tin with alkali metal sulfides in the presence of Ss at 200-450 °C gives a variety of alkali metal tin sulfides depending on the ratio of the starting materials, the reaction temperature, and the alkah metals (Scheme 30) [90]. These alkali metal tin sul-... 

Nitrogen adsorption experiments showed a typical t)q5e I isotherm for activated carbon catalysts. For iron impregnated catalysts the specific surface area decreased fix>m 1088 m /g (0.5 wt% Fe ) to 1020 m /g (5.0 wt% Fe). No agglomerization of metal tin or tin oxide was observed from the SEM image of 5Fe-0.5Sn/AC catalyst (Fig. 1). In Fig. 2 iron oxides on the catalyst surface can be seen from the X-Ray diffractions. The peaks of tin or tin oxide cannot be investigated because the quantity of loaded tin is very small and the dispersion of tin particle is high on the support surface. 

An interesting 3D superlattice of the main group metal tin has recently been generated [36]. When Sn(NMe2)2 is treated with hexadecylamine and HCl, perfect 3D superstructures of monodisperse 18 x 15nm Sn nanoparticles could be characterized. 

In this case iron would serve as the anode (Fe -> Fe2+ + 2 e ) and tin as the cathode (Sn2+ + 2e -> Sn). In this situation, iron tends to dissolve in the electrolyte, and this process is also known as galvanic corrosion of the less noble metal (which is iron in this case) in comparison with the more noble metal (tin) in this system. The reversible emf of the corrosion cell would be ... 

Among all the metals listed in Table 7.6, the MFE for the production of secondary tin is as much as 91% of the MFE for the production of primary tin. This unusual situation arises from the fact that tinned steel contains only 0.2-0.3% tin, and the processing of this source involves dissolution of the tin in a caustic solution, followed by an energy-intensive electrowinning operation to obtain metallic tin. An advantage is that the detinned steel scrap is suitable for steel manufacture. 

The Aiiotropes of Tin Tin Pest. Metallic tin may occur in three allotropic forms (see Textbox 19) the common form of tin, also known as white tin or beta tin, is stable at ambient temperatures its stability extends between -18°C and 170°C below -18°C tin is converted to a gray powdery allotrope, known as alpha tin or tin pest. A third allotrope, known as rhombic tin, is the form of tin stable at temperatures above 170°C. If ordinary white tin remains for extended periods of time at temperatures below -18°C, therefore, it is slowly converted to the gray, brittle, and powdery allotrope tin pest the conversion is accelerated at still lower temperatures. Tin objects kept in regions of the world where extremely low temperatures (below -18°C) prevail, initially... 

Caley, E. R. and D. T. Easby (1964), New evidence of tin smelting and the use of metallic tin in pre-Conquest Mexico, Adas del XXXV Congreso Internadonal de Ameri-canistas, Mexico, pp. 507-517. 

A mixture can be ignited with a match, and reduction to metallic tin proceeds with incandescence. 

At atmospheric pressure, pure solid tin adopts two structures or allotropes, depending on temperature. At room temperature white metallic tin is stable but, at temperatures below 13°C, white tin undergoes a phase transformation into gray tin. White tin (also known as / -tin) adopts a body-centered tetragonal crystal structure (Fig. 8.5.1). Allotropic gray tin (a-tin) crystallizes in a cubic diamond... 

It is known that in the process of electrochemical cycling of tin oxide-based thin films versus lithium metal there are at least two reactions in standard alkylcarbonate electrolyte based on lithium salts [1], The first of them leads to formation of metallic tin on the first cycle ... 

In some cases, metallic tin reacts directly with an alkyl halide to produce mixed alkyl halide compounds. 

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