Cadmium elements

By comparison with zinc or cadmium, elements such as aluminium, gallium and indium from the third column, silicon, germanium and tin from the fourth column and antimony from the fifth column, dissolve to the extent 1 1/2 1/3 1U ... 

Numerous power packs have a hard plastic shell accounting for 12 to 15% of then-weight. The shell can be broken and separated from the individual nickel-cadmium elements by means of, for example, a magnetic separator. 

Group IIB and know that this means the group of elements zine. cadmium and mercury, whilst Group IIA refers to the alkaline earth metals beryllium, magnesium, calcium, barium and strontium. 

These elements formed Group IIB of Mendeleef s original periodic table. As we have seen in Chapter 13, zinc does not show very marked transition-metaf characteristics. The other two elements in this group, cadmium and mercury, lie at the ends of the second and third transition series (Y-Cd, La-Hg) and, although they resemble zinc in some respects in showing a predominantly - - 2 oxidation state, they also show rather more transition-metal characteristics. Additionally, mercury has characteristics, some of which relate it quite closely to its immediate predecessors in the third transition series, platinum and gold, and some of which are decidedly peculiar to mercury. 

Fluorspar occurs in two distinct types of formation in the fluorspar district of southern Illinois and Kentucky in vertical fissure veins and in horizontal bedded replacement deposits. A 61-m bed of sandstone and shale serves as a cap rock for ascending fluorine-containing solutions and gases. Mineralizing solutions come up the faults and form vein ore bodies where the larger faults are plugged by shale. Bedded deposits occur under the thick sandstone and shale roofs. Other elements of value associated with fluorspar ore bodies are zinc, lead, cadmium, silver, germanium, iron, and thorium. Ore has been mined as deep as 300 m in this district. 

Comparing the relative abundance of the rare earths and the other elements Hsted in Table 1, the rare earths are not so rare. Cerium, the most abundant of the rare-earth elements is roughly as abundant as tin thuHum, the least abundant, is more common than cadmium or silver. Over 200... 

For nuclear applications, the cadmium and boron (high capture cross-section elements) shall be defined as cadmium, max % 0.0001 or 0.00005 boron, max % 0.00007 or 0.00003. 

Mercury Telluride. Compounds of mercury with tellurium have gained importance as semiconductors with appHcations in infrared detection (9) and solar cells (10). The ratio of the components is varied, and other elements such as cadmium, zinc, and indium are added to modify the electronic characteristics. 

Refining Processes. AH the reduction processes yield an impure metal containing some of the minor elements present in the concentrate, eg, cadmium in 2inc, or some elements introduced during the smelting process, eg, carbon in pig iron. These impurities must be removed from the cmde metal in order to meet specifications for use. Refining operations may be classified according to the kind of phases involved in the process, ie, separation of a vapor from a Hquid or soHd, separation of a soHd from a Hquid, or transfer between two Hquid phases. In addition, they may be characterized by whether or not they involve oxidation—reduction reactions. 

Some elements found in body tissues have no apparent physiological role, but have not been shown to be toxic. Examples are mbidium, strontium, titanium, niobium, germanium, and lanthanum. Other elements are toxic when found in greater than trace amounts, and sometimes in trace amounts. These latter elements include arsenic, mercury, lead, cadmium, silver, zirconium, beryUium, and thallium. Numerous other elements are used in medicine in nonnutrient roles. These include lithium, bismuth, antimony, bromine, platinum, and gold (Eig. 1). The interactions of mineral nutrients with... 

Solders are alloys that have melting temperatures below 300°C, formed from elements such as tin, lead, antimony, bismuth, and cadmium. Tin—lead solders are commonly used for electronic appHcations, showing traces of other elements that can tailor the solder properties for specific appHcations. 

Modifications to Precipitates. Silicon is sometimes added to Al—Cu—Mg alloys to help nucleate S precipitates without the need for cold work prior to the elevated temperature aging treatments. Additions of elements such as tin [7440-31-5] Sn, cadmium [7440-43-9] Cd, and indium [7440-74-6] In, to Al—Cu alloys serve a similar purpose for 9 precipitates. Copper is often added to Al—Mg—Si alloys in the range of about 0.25% to 1.0% Cu to modify the metastable precursor to Mg2Si. The copper additions provide a substantial strength increase. When the copper addition is high, the quaternary Al CuMg Si Q-phase must be considered and dissolved during solution heat treatment. 

Titanium Dibromide. Titanium dibromide [13873-04-5] a black crystalline soHd, density 4310 kg/m, mp 1025°C, has a cadmium iodide-type stmcture and is readily oxidized to trivalent titanium by water. Spontaneously flammable in air (142), it can be prepared by direct synthesis from the elements, by reaction of the tetrabromide with titanium, or by thermal decomposition of titanium tribromide. This last reaction must be carried out either at or below 400°C, because at higher temperatures the dibromide itself disproportionates. 

Although it is only slowly oxidized in moist air at ambient temperature, cadmium forms a fume of brown-colored cadmium oxide [1306-19-0] CdO, when heated in air. Other elements which react readily with cadmium metal upon heating include the halogens, phosphoms, selenium, sulfur, and tellurium. The standard reduction potential for the reaction... 

The intermetallic compounds with Group 16 (VIA) elements including CdS, CdSe, and CdTe have interesting semiconductor properties for photoconductors, photovoltaic cells, and ir windows. Cadmium sulfide is widely used as a phosphor in television tubes. 

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