Aluminum and Beryllium

Because of numerous similarities in their properties and reactions, aluminum and beryllium will be described together even though they are in different groups of the periodic table. Although it is not completely understood, there is some indication that the accumulation of aluminum in the brain may have some relationship to Alzheimer s disease, and beryllium compounds are extremely toxic. 

Naturally occurring Na3AlF6 is not readily available in sufficient quantity for the production of aluminum, but it can be produced by the reaction 

There is a complex relationship among the oxide, hydroxide, and hydrous oxide of aluminum. Conversion between several phases is possible as a result of the reactions 

Beryllium shows similar behavior as a result of forming bonds to oxygen  

Compounds of beryllium and aluminum are substantially covalent as a result of the high charge -to-size ratio, which causes polarization of anions and very high heats of hydration of the ions ( —2487kJ mol-1 for Be2+ and — 4690kJ mol-1 for Al3+). 

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To achieve higher energy in solid proplnts the most notable advances were achieved with the addition of aluminum and beryllium to both double-base and composite proplnts. Energy in this case is commonly equated to high specific impulse. Later developments added aluminum hydride and beryllium hydride to this list. In Table 16, the specific impulse performance of proplnts using AP with various metals and hydrides is compared to those systems without these additives (Ref 43)... 

Aluminum and beryllium have a diagonal relationship. Compare the chemical equations for the reaction of aluminum with aqueous sodium hydroxide to that of beryllium with aqueous sodium hydroxide. 

Low concentrations of aluminum and beryllium can be determined by chelating with 8-hydroxyquinoline and extracting the chelates into MIBK and aspirating into a N20-acetylene flame. 

Bahrain, M., T. Madrakian, E. Bozorgzadeh, and A. Afkhami. 2007. Micelle-mediated extraction for simultaneous spectrophotometric determination of aluminum and beryllium using mean centering of ratio spectra. Talanta 72 408-414. 

Use Fluoridation, laundry sours, opalescent glass, vitreous enamel frits, metallurgy (aluminum and beryllium), insecticides and rodenticides, chemical intermediate, glue, leather and wood preservative, moth repellent, manufacture of pure silicon. 

Sealed Proportional Counter. A sealed proportional counter is shown schematically in Fig. 8.24(b). The windows are thicker, so they do not leak. Window materials include polymers, mica, aluminum, and beryllium. The filler gas used in a sealed proportional counter may be Ne, Kr, or Xe. Window and gas combinations are optimized for the wavelength of radiation to be detected A1 and Ne would be best for light elements, for example. 

Beryllium Aluminate, Be(A10j)o.—Occurs in nature as chryso-beryl (cymophane, alexandrite) and prepared artificially by Ebel-men (1851 3) by fusing theoretical portions of alumina and beryllia in boric anhydrid and later, by Hautefeuille and Perrey by fusing a mixture of the oxides of aluminum and beryllium in leucite or nephelite. 

States that fusing crude BeO with HF. KF and treating the fused mass with boiling water and slight amount of HP and recrystallization is the best known (1864) method of producing a chemically pure salt of beryllium. Under these conditionss the aluminum is separated as the very insoluble AlFj 3KF. Also states that NaF precipitates the aluminum probably quantitatively from a mixture of the fluorides of aluminum and beryllium. 

Gives method of analysis and discusses method of St. Clair Deville (Annales., 38). Says it is one of the most accurate in analytical chemistry. Separates beryllium from iron by reducing iron in platinum tube in a current of hydrogen and then volatilizing in a current of HCl. Aluminum and beryllium not efifected. See 1850, Rivot. 

Aluminum and beryllium copper are often used for blow molds for plastic bottles. Beryllium copper has better heat transfer and resistance to wear, but is more expensive. Aluminum is used most because it is significantly less expensive and provides good heat transfer, although it does wear more quickly. Because blow molds are not subject to pressures nearly as high as the pressures in injection molding, the molds can be less rugged. Beryllium copper or steel inserts are often used in the parts of the mold most subject to wear, such as the pinch-off in an extrusion blow mold. A typical blow mold can produce about 12 million containers before it must be discarded, provided some refurbishing is done periodically. 

On the other hand, the number of highly reactive chemicals that advance from the sta of laboratory curiosities to commercial items is constantly increasing, Some of these are sodium hydride (NaH), lithium aluminum hydride (LiAlH ), lithium borohydride (LiBH ), aluminum and beryllium borohydride, Al(BH4)3 and BefBH ), the sodium salt of nitromethane sodium methane nitronate or if one prefers sodium nitro methanate (HjCNOgNa), - and barium carbide (BaCg)/ all of which can flame on contact with water. Again, it must be stressed that particle size and other conditions of exposure may determine whether there is flaming or merely a violent reaction on exposure to water, air, or both. 

The earth metals and the earths themselves were in the same place, according to their similarities, hut one had not successfiilly ordered them. It is true that they form boron and silicon, aluminum and beryllium, yttrium and cerium, which are special groups, hut each of them lacked in the third member. The magnesium stayed alone and the zirconium belongs to the titanium and the tin. 

Only one bimetallic mechanism is presented here, as an example, the one originally proposed by Natta. He felt that chemisorptions of the organometallic compounds to transition metal halides take place during the reactions. Partially reduced forms of the di- and tri-chlorides of strongly electropositive metals with a small ionic radius (aluminum, beryllium, or magnesium) facilitate this. These chemisorptions result in formations of electron-deficient complexes between the two metals. Such complexes contain alkyl bridges similar to those present in dimeric aluminum and beryllium alkyls. The polymeric growth takes place from the aluminum-carbon bond of the bimetallic electron-deficient complexes . ... 

Refractive lenses act as a normal conventional lens and we can apply the Gauss lens formula, which relates the source distance L-, the image distance L2, and the focal distance F via L2 = FLi(Li - F). The diffraction-limited resolution of the lens A is defined by an effective aperture A = 0.75A/2NA, where the numerical aperture is NA = Aeff/2L2. is the effective aperture of the lens, reduced by photon absorption and scattering, compared with the geometrical aperture 2Rq. Nowadays, the parabolic refractive lenses, made of aluminum and beryllium, are available and widely used for hard X-ray microscopy applications providing resolution in the order of 300-500 nm. 

Although some of these salt-like carbides have high melting point (for instance beryllium carbide sublimes above 2100°C), they are decomposed readily by water and/or dilute acids at ordinary temperatures and thus do not meet the refractory criteria of this book. However, this does not necessarily detract from their usefulness. Aluminum and beryllium carbides, the three actinide carbides ThC, UC and PuC, and several lanthanide (rare earth) carbides are important industrial materials in several areas such as atomic energy and others. 

Alfrey AC, LeGendre GR, Kaehny WD (1976) The dialysis encephalopathy syndrome. Possible aluminium intoxication. N Engl J Med 294 184-188 Antonny B, Chabre M (1992) Characterization of the aluminum and beryllium fluoride species which activate transducin. J Biol Chem 267 6710-6718 Antonny B, Sukumar M, Bigay J, Chabre M, Higashijima T (1993) The mechanism of aluminum-independent G-protein activation by fluoride and magnesium. J Biol Chem 268 2393-2402... 

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