Density cadmium compounds

The thermodynamic properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries, as it may provide a considerably higher energy density than the commonly used lead-acid and nickel-cadmium systems, while in contrast to Pb and Cd, magnesium is inexpensive, environmentally friendly, and safe to handle. However, the development of Mg-ion batteries has so far been limited by the kinetics of Mg " " diffusion and the lack of suitable electrolytes. Actually, in spite of an expected general similarity between the processes of Li and Mg ion insertion into inorganic host materials, most of the compounds that exhibit fast and reversible Li ion insertion perform very poorly in Mg " ions. Hence, there... 

Both compounds crystallize with the cadmium diiodide structure (space group P3ml) as previously reported on polycrystalline samples.3 For platinum disulfide, ao = 3.542(1) A and c0 = 5.043(1) A, and for platinum ditelluride, a0 = 4.023(1) A and c0 = 5.220(3) A. Direct chemical analysis for the component elements was not carried out. Instead, precision density and unit-cell determinations were performed to characterize the samples. The densities of both compounds as determined by a hydrostatic technique with heptadecafluorodeca-hydro-l-(trifluoromethyl)naphthalene as the density fluid4 indicated that they are slightly deficient in platinum. For platinum disulfide, = 7.86 g/cm3 and Pmeas = 7.7(1) gm/cm3, and for platinum ditelluride, p = 10.2 gm/cm3 and Pmeas = 9.8(1) gm/cm3. In a typical experiment an emission spectrum of the platinum disulfide showed that phosphorus was present in less than 5 ppm. A mass spectroscopic examination of the platinum ditelluride revealed a small doping by sulfur (less than 0.4%) and traces of chlorine and phosphorus (less than 100 ppm). 

Many studies on the direct reaction of methyl chloride with silicon-copper contact mass and other metal promoters added to the silicon-copper contact mass have focused on the reaction mechanisms.7,8 The reaction rate and the selectivity for dimethyldichlorosilane in this direct synthesis are influenced by metal additives, known as promoters, in low concentration. Aluminum, antimony, arsenic, bismuth, mercury, phosphorus, phosphine compounds34 and their metal complexes,35,36 Zinc,37 39 tin38-40 etc. are known to have beneficial effects as promoters for dimethyldichlorosilane formation.7,8 Promoters are not themselves good catalysts for the direct reaction at temperatures < 350 °C,6,8 but require the presence of copper to be effective. When zinc metal or zinc compounds (0.03-0.75 wt%) were added to silicon-copper contact mass, the reaction rate was potentiated and the selectivity of dimethyldichlorosilane was enhanced further.34 These materials are described as structural promoters because they alter the surface enrichment of silicon, increase the electron density of the surface of the catalyst modify the crystal structure of the copper-silicon solid phase, and affect the absorption of methyl chloride on the catalyst surface and the activation energy for the formation of dimethyldichlorosilane.38,39 Cadmium is also a structural promoter for this reaction, but cadmium presents serious toxicity problems in industrial use on a large scale.41,42 Other metals such as arsenic, mercury, etc. are also restricted because of such toxicity problems. In the direct reaction of methyl chloride, tin in... 

Many dithiocarbamate complexes of zinc, silver, cadmium or mercury improve emulsion stability, including bis(dibenzyldithiocarbamato)-zinc(II) or -cadmium(II) and silver(I) diethyldi-thiocarbamate. Cadmium salts, mixed with citric acid or tartaric acid and added to the emulsion, are reported to be effective. Mercury(II) complexes of ethylenediaminetetraacetic acid (EDTA) and related ligands and of solubilized thiols such as (4) can be used. Other coordination compounds reported include EDTA and related ligand complexes of Co and Mn, mixtures of Co salts with penicillamine (5) and macrocyclic complexes of Ag such as (6). The latter compounds may be used in diffusion transfer systems in which transferred maximum densities are stabilized. 

Mercury. Sometimes called quicksilver, mercury is the only common metal that is liquid at ordinary temperatures. It is a feir conductor of electricity and of high density. It is used in barometers and thermometers, to recover gold from its ore, and to manu-fecture chlorine and sodium hydroxide. Its vapor is used in street lights, fluorescent lamps, and advertizing signs. Mercury compounds have various uses, such as insecticides, rat poisons, disinfectants, paint pigments, and detonators. Mercury easily is alloyed with silver, gold, and cadmium. 

Cadmium Red n Pigment Red 108 (77202). Pigments of Calcined coprecipitations of compounds of cadmium, sulfur, and selenium a brilliant red pigment, opaque, with good staining power, fast to light, unaffected by exposure to sulfur fumes considerable resistance to heat. Density, 4.9 g/cm (41 Ib/gal) O.A., 20 lb/100 lb. 

Cadmium is a transition metal in group IIB of the periodic table of elements. The metal is bluish-white to silver-white. At room temperature, it has a hexagonal close-packed crystal structure. Eight stable isotopes are known to be present in natui . The atomic weight of cadmium is 112.4 and the atomic number 48. The density at 25°C is 8.6 g/cm the melting point 321°C and the boiling point 765°C. The most common oxidation state is +2. " The most important compounds are cadmium acetate, cadmium sulfide, cadmium sulfoselenide, cadmium stearate, cadmium oxide, cadmium carbonate, cadmium sulfate, and cadmium chloride. The acetate, chloride, and sulfate are soluble in water, whereas the oxide and sulfide are almost insoluble. ... 

Non Aqueous Solvents. Several ll-VI compounds have also been electrodeposited from non-aqueous solvents. The first report was by BaranskI and Fawcett (60) in i960. Their approach was to deposit cationic species eiectrochemically from a solution containing elemental chalcogenide, dimethylsulfoxide (DMSO), dimethylformamide (DMF) and ethylene glycol (EG). A typical CdS deposition utilized a solution of 6 gm/l of sulfur and 10 gm/l of cadmium chloride. This was electrolyzed at 110°C with a current density of < 2.5 mA/cm . The quality of the CdS deposit was independent of both the sulfur and cadmium chloride concentration used and was not affected by the addition of 10% water. The deposit composition was solution temperature dependent, however, becoming highiy non-stoichlometric below 90°C. X-ray diffraction data showed that the crystallites In the film were all oriented with their [ill] planes parallel to the electrode surface. The resistivity of these films was about 10 n cm which could be lowered by addition of sodium iodide to the solution. 

CdTe is a crystalline compound with a cubic zinc blende (sphalerite) crystal structure (lattice constant of 6.481 A), a direct band gap of 1.5 eV, an ideal match to the solar spectrum, and an extinction coefficient around 5 x 10" cm . " ° The intrinsic defects include cadmium interstitials and cadmium vacancies, and extrinsic doping can be achieved using In (donor) substitution or Cu, Ag, Au (acceptor) substitution for Cd. The mobilities have been measured to be up to 1100 cm s for electrons and up to 8 cm s for holes. Dopant densities up to 10 cm ... 

---