Arsenic germanium

Studies of metal alkyls and aryls deal largely with arsenic, germanium and antimony, although some work has also been done on tellurium, mercury, thallium, bismuth and lead. The major contributions can be neatly divided into four periods early studies by Maddock, Sutin and H 1155).56).57) studies by the Polish >- >- and the Strasbourg >- 2).79) groups, work by Riedel and and most recently a series... 

Both alkyl and aryl metals have been studied, but not a very wide range of compounds. Several studies of triphenylarsene and triphenylstibine have been done. Methyl and ethyl compounds of arsenic, germanium, mercury, bismuth, and lead essentially complete the list. In virtually all cases the results have been clouded by difficulties in effecting chemical separation without altering the product distribution. The results do, nonetheless, lead to valid and important conclusions. 

Fig. 12.4 illustrates the complex interactions induced by the presence of silica between reaction temperature, sulphuric acid acidity and the apparent level of phosphorus found. By careful control of acid concentration and reaction temperature, interference by silica can be minimized. Arsenic, germanium and bismuth would interfere in the method but not at the low levels normally encountered in sediment in water samples. 

Schroeder HA, Balassa JJ. 1967. Arsenic, germanium, tin and vanadium in mice Effects on growth, survival and tissue levels. J Nutr 92 245-252. 

Weller, W. W., and Kelley, K. K., 1964, Low-temperature heat capacities and entropies at 298.15 °K of sulfides of arsenic, germanium, and nickel U.S. Bureau of Mines Report Investigations 6511, 7 p. 

CARBANIONS STABILIZED BY ARSENIC, GERMANIUM, TIN, ANTIMONY, LEAD AND BISMUTH 203... 

Gasification stimulated by non-thermal plasma excitation and subsequent dissociation of H2 was also observed in experiments with production of hydrides of sulfur, arsenic, germanium, tin, tellurium, and selenium (Bonhoeffer, 1924 Pearson, Robinson, Stoddart, 1933 Radford, 1964). The mechanism of hydride production includes in this case volume and surface dissociation of excited hydrogen molecules, chemisorption of atomic... 

It is difficult to make stable hollow cathodes from certain elements, particularly those that are volatile, such as arsenic, germanium, or selenium. The HCLs of these elements have short lifetimes and low intensities. An alternative light source has been developed in the EDL. A commercial EDL design is shown in Fig. 6.7. A small amount of metal or a salt of the element whose spectrum is desired is sealed into a quartz bulb with a low pressure of Ar gas. The bulb is shown centered inside the coils in Fig. 6.7. The coils are part of a self-contained RF generator. When power is applied to the coils, the RF field generated will couple with the metal or salt in the quartz bulb. The coupled energy will vaporize... 

There is, in fact, no clear-cut distinction between metals and non-metals. In the periodic table, there is a change from metallic to non-metallic properties across the table, and an increase in metalUc properties down a group. Consequently there is a diagonal around the center of the table (B, Si, As, Te) in which there is a borderline between metals and non-metals, and the metalloids are the borderline cases. Elements such as arsenic, germanium, and tellurium are semiconductors, but other elements are often said to be metalloids according to their chemical properties. Tin, for instance, forms salts with acids but also forms stan-nates with alkalis. Its oxide is amphoteric. Note also that tin has metallic (white tin) and non-metallic (gray tin) allotropes. 

Although infrequently used, electrochemical generation of the hydrides is also possible and has been applied to the determination of arsenic and tin in a batch approach and to antimony, arsenic, germanium, selenium, and tin using a flow-through electrolytic cell. The hydride is generated in the cathodic space of an electrolytic cell, with concurrent oxidation of water in the anodic compartment, as illustrated by the reaction below. Here, Me-E represents the reduced analyte element on the metallic cathode surface (Me) ... 

A crystal of germanium containing some atoms of arsenic (germanium doped with arsenic) has extra electrons in the excited orbitals, because... 

Chalmers, R.A. and Sinclair, A.G., Analytical applications of p-heteropoly acids. Part I. Determination of arsenic, germanium and silicon, Analytica Chimica Acta 33, 384,1965. 

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