For tin oxide

Our first example that attempts to imravel this complexity is entitled Gas-Phase Thermochemistry and Mechanism of Organometallic Tin Oxide CVD Precursors . The authors, M. Allendorf and A.M.B. van Mol, describe the development of quantum chemistry methods that can predict heats of formation for a broad range of tin compounds in the gas phase, which need to be considered when Sn(CH3)4 or (CH3)2SnCl2 and other tin alkyls are used as precursors together with oxygen and water for tin oxide deposition. 

ZnO displays similar redox and alloying chemistry to the tin oxides on Li insertion [353]. Therefore, it may be an interesting network modifier for tin oxides. Also, ZnSnOs was proposed as a new anode material for lithium-ion batteries [354]. It was prepared as the amorphous product by pyrolysis of ZnSn(OH)6. The reversible capacity of the ZnSn03 electrode was found to be more than 0.8 Ah/g. Zhao and Cao [356] studied antimony-zinc alloy as a potential material for such batteries. Also, zinc-graphite composite was investigated [357] as a candidate for an electrode in lithium-ion batteries. Zinc parhcles were deposited mainly onto graphite surfaces. Also, zinc-polyaniline batteries were developed [358]. The authors examined the parameters that affect the life cycle of such batteries. They found that Zn passivahon is the main factor of the life cycle of zinc-polyaniline batteries. In recent times [359], zinc-poly(anihne-co-o-aminophenol) rechargeable battery was also studied. Other types of batteries based on zinc were of some interest [360]. 

R(200 ppm of alcohol vapor in air) are 50 and 140 for tin oxide (Sn0x) and palladium-gold/SnOx (PdAu/SnOx) sensors, respectively while the values of R(50 ppm of N0X in air)/R(air) are 60 and 5 for SnOx and PdAu/SnOx sensors, respectively. Possible sensing mechanisms based on XPS, Kelvin probe, Hall and electrical conductivity measurements are also discussed. 

The reactive ion etching system used for the delineation of tin oxide thin film is a diode RF sputtering system and was described in our earlier paper (8). For tin oxide etching, the etching parameters used are as follows ... 

The sensing mechanisms of the tin oxide based sensors have been discussed in many publications (9,10,11). The most widely accepted model for tin oxide based sensors operated at temperatures <400°C is based on the modulation of the depletion layer width in the semiconductor (sensor) due to chemisorption as illustrated schematically in Figure 6. For C2H 0H and Sn0x (or PdAu/Sn0x) interaction, the possible reaction steps may be expressed by the following equations ... 

Crary S B 1986 Recent advances and future prospects for tin-oxide gas sensors... 

The results of animal experiments have shown that tin accumulates in the kidneys, liver and bone, but have not found any evidence of carcinogenicity or teratogenicity. The ACGIH TLV for tin metal is 2 mg/m and for tin oxide is 0.1 mg/m. ... 

Polarizing potentials could be applied in the form of pulses, and still gave rise to a diminution in the amount of adsorbed bacteria. Figure 4 demonstrates such results for tin oxide glass electrodes in 3% saline solution. 

The latest research indicates that application of a suitable coating can render dies considerably more durable. The most promising candidates appear to be a -C H or DLC (diamond-like carbon) metal-free amorphous carbon coatings. They provide a very poor key for tin oxide deposits and alkaline cleaning is easy. In [184], cleaning after 3000 to 4000 cycles was sufficient. The die did not have to be remachined until it had performed 15,000 cycles. Industrial trials with these coated dies is in progress at this time [184]. 

Figure C1.5.12.(A) Fluorescence decay of a single molecule of cresyl violet on an indium tin oxide (ITO) surface measured by time-correlated single photon counting. The solid line is tire fitted decay, a single exponential of 480 5 ps convolved witli tire instmment response function of 160 ps fwiim. The decay, which is considerably faster tlian tire natural fluorescence lifetime of cresyl violet, is due to electron transfer from tire excited cresyl violet (D ) to tire conduction band or energetically accessible surface electronic states of ITO. (B) Distribution of lifetimes for 40 different single molecules showing a broad distribution of electron transfer rates. Reprinted witli pennission from Lu andXie [1381. Copyright 1997 American Chemical Society.

Stannate(II) ions are powerful reducing agents. Since, for tin, the stability of oxidation state -b4 is greater than that of oxidation state -b2, tin(II) always has reducing properties, but these are greater in alkaline conditions than in acid (an example of the effect of pH on the redox potential, p. 101). 

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

Acetylsucrose [63648-81-7] has been prepared in 40% yield by direct acetylation of sucrose using acetic anhydride in pyridine at 40° C (36). The 6-ester has subsequently been obtained in greater than 90% yield, by way of 4,6-cycHc orthoacetate. Other selective methods for the 6-acylated derivatives include the use of alkyl tin reagents such as dibutyl tin oxide (37) and of dibutyl stannolane derivatives (38). Selective acetylation of sucrose by an enzymic process has also been described. Treatment of sucrose with isopropenyl acetate in pyridine in the presence of Lipase P Amano gave, after chromatography, 6-0-acetylsucrose (33%) and 4/6-di-O-acetylsucrose (8%). The latter compound has been obtained in 47% yield by the prolonged treatment (39). 

In a fire-assay method used at the smelters, a weighed quantity of concentrate is mixed with sodium cyanide in a clay or porcelain cmcible and heated in a muffle furnace at red heat for 20—25 min. The tin oxide is reduced to metal, which is cleaned and weighed. Preliminary digestion of the concentrate with hydrochloric and nitric acids to remove impurities normally precedes the sodium cyanide fusion. 

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