Beryllium isolation

Gr. beryllos, beryl also called Glucinium or Glucinum, Gr. glykys, sweet) Discovered as the oxide by Vauquelin in beryl and in emeralds in 1798. The metal was isolated in 1828 by Wohler and by Bussy independently by the action of potassium on beryllium chloride. 

BeryUium chloride [7787-47-5], BeCl2, is prepared by heating a mixture of beryUium oxide and carbon in chloride at 600—800°C. At pressures of 2.7—6.7 Pa (0.02—0.05 mm Hg) beryllium chloride sublimes at 350—380°C. It is easily hydrolyzed by water vapor or in aqueous solutions. BeryUium chloride hydrate [14871-75-1] has been obtained by concentrating a saturated aqueous solution of the chloride in a stream of hydrogen chloride. ChloroberyUate compounds have not been isolated from aqueous solutions, but they have been isolated from anhydrous fused salt mixtures. 

With modern detectors and electronics most Enei -Dispersive X-Ray Spectroscopy (EDS) systems can detect X rays from all the elements in the periodic table above beryllium, Z= 4, if present in sufficient quantity. The minimum detection limit (MDL) for elements with atomic numbers greater than Z = 11 is as low as 0.02% wt., if the peaks are isolated and the spectrum has a total of at least 2.5 X 10 counts. In practice, however, with EDS on an electron microscope, the MDL is about 0.1% wt. because of a high background count and broad peaks. Under conditions in which the peaks are severely overlapped, the MDL may be only 1—2% wt. For elements with Z < 10, the MDL is usually around 1—2% wt. under the best conditions, especially in electron-beam instruments. 

Alkyl derivatives of the Group 2 metals (Be, Mg, Ca, Sr, Ba) supported by poly(pyrazolyl)borato ligation have only been isolated for the lighter congeners, beryllium and magnesium. 

Soft, silver white metal that is isolated in the tiniest of amounts. All isotopes are radioactive, the longest-lived has a half-life of 22 years. The element is an intermediate in the decay series of 235U. Strong alpha emitter that is used in radioactivation analysis and forms an effective neutron source with beryllium. 

Liquid He II in an isolating tube has also been used as a switch [46]. Thermal switches can also be produced using materials, like beryllium, graphite or stainless steel, whose thermal conductivity varies rapidly with temperature [47-49]. 

The interaction of beryllium with nitrilotripropionic acid (H3ntp) has been investigated in some detail (244). This acid forms a strong complex (log Kt = 9.24) that can be isolated as a solid. The crystal structure of the anion [Be(ntp)] is shown in Fig. 23. The structure confirms the coordination of the nitrogen atom along with an oxygen atom from each carboxyl group. 

Polyalcohols do not generally interact noticeably with beryllium, probably on account of the low acidity of the alkyl-OH group. Two exceptions are known where solid compounds have been isolated. The complex anion [bis(meso-oxolane-3,4-diolato)Be]2 has been shown to contain two anionic diolato ligands (258). 

The fact that NHCs form stable compounds with beryllium, one of the hardest Lewis acids known and without p-electrons to back donate, shows the nu-cleophilicity of these ligands. Reaction of l,3-dimethylimidazolin-2-ylidene with polymeric BeCl2 results in the formation of the neutral 2 1 adduct 23 or the cationic 3 1 adduct 24. The first NHC-alkaline earth metal complex to be isolated was the 1 1 adduct 25 with MgEt2- Whereas l,3-dimesitylimidazolin-2-ylidene results in the formation of a dimeric compound, the application of sterically more demanding l,3-(l-adamantyl)imidazolin-2-ylidene gives a monomeric adduct. ... 

D uring the last two decades of the eighteenth century, investigations were made which foreshadowed the discovery of chromium, molybdenum, tungsten, uranium, tellurium, chlorine, titanium, and beryllium but some of these elements were not actually isolated until much later. For the sake of simplicity, only the closely related elements, tungsten, molybdenum, uranium, and chromium, will be considered in this chapter. 

Friedrich Wohler, 1800-1882. German chemist Student of Leopold Gmelm and Berzelius. He was the first person to synthesize urea and to describe the properties of metallic aluminum. He isolated aluminum, beryllium, and yttrium by the action of potassium on the respective chlorides. 

Vauquelin recognizes beryllium (glucinum) and isolates chromium. Beryllium was first isolated in 1828 by Wohler. 

Wohler isolates beryllium. Bussy isolates it independently. 

Chlorine and fluorine in beryllium metal are isolated by pyrohydrolysis or by distillation (21). Fluoride and chloride in the condensate are determined by ion-selective electrode or colorimetrically. 

Beryllium is important as a sensor support material in advanced fire-control and navigation systems for military helicopters and fighter aircraft utilizing the low weight and high stiffness of the material to isolate instrumentation from vibration. It is also used for scanning mirrors in tank fire-control systems. 

In 1797, Vauquclin discovered beryllium to be a constituent of the minerals beryl and emerald. Soluble compounds of the new element tasted sweet, so it was first knov/n as glucinium from Ihe corresponding Greek term. Quarrels over the name of the element were perpetuated by the simultaneous and independent isolations of metallic beryllium in 1828 by Wohler and Bussy. Both reduced beryllium chloride with metallic potassium in a platinum crucible. The name beryllium and symbol Be were officially recognized by the ILIPAC til 1957. 

In all of, these cases substitution of the second alkyl can then occur to yield the dialkoxide or diphenoxide. This allowed the isolation of the monomeric beryllium phenoxide Be(OAr )2 (OAr = 2,6-di-t-butylphenoxide).98 The alkyls of the Group IV metals, MR (M = Ti, Zr, Hf), undergo rapid reactions with common alcohols and phenols yielding eventually the corresponding tetra-alkoxides or -phenoxides and four equivalents of alkane.97,100 With very bulky substituted alcohols or phenols the reactivity can be very sluggish, in some cases leading to only partial substitution (equation 28). 66,100... 

Tandon and Chhor have reported the formation of 3,4-diphenyl-l,2-diazete 201, a very rare example of an isolated diazete, by C-C bond formation <2004LOC40>. l,4-Dichloro-l,4-diphenyl-2,3-diaza-l,3-butadiene 238 was treated with beryllium in THF to give a good yield (56%) of 3,4-diphenyl-l,2-diazete 201 (Equation 29). During the last decade, this strategy has not been used. 

The zinc compound 1 begins to decompose at 10°C to zinc and hydrocarbons, but the magnesium and beryllium complexes are more stable. Crystalline adducts 2 can be isolated on addition of TMEDA. The 1H-NMR spectra of 2 (M = Mg, Zn) show averaged AB2X patterns on account of rapid fluxional processes. The spectra can be frozen out at low temperatures, indicating terminally bonded r l-pentadienyl groups (85-87). 

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