Beryllium Metallic

Beryllium is found in some 30 mineral species, the most important of which are bertrandite, beryl, chrysoberyl, and phenacite. Aquamarine and emerald are precious forms of beryl. Beryl and bertrandite are the most important commercial sources of the element and its compounds. Most of the metal is now prepared by reducing beryllium fluoride with magnesium metal. Beryllium metal did not become readily available to industry until 1957. 

Beryllium and aluminum are virtually insoluble in one another in the soHd state. The potential therefore exists for an aluminum—beryllium metal matrix composite with lower density and higher elastic modulus, ie, improved specific modulus, than conventional aluminum alloys produced by ingot or powder metal processing. At least one wrought composite system with nominally 62 wt % Be and 38 wt % A1 has seen limited use in aerospace appheations (see Composites). 

Beryllium carbide slowly hydroly2es to beryllium oxide and methane in the presence of atmospheric moisture although months may be requited to complete the reaction. Any carbon contained in beryllium metal is present as the carbide because the solubiUty of carbon in beryllium is extremely low. 

Beryllium Nitride. BeryUium nitride [1304-54-7], Be N2, is prepared by the reaction of metaUic beryUium and ammonia gas at 1100°C. It is a white crystalline material melting at 2200°C with decomposition. The sublimation rate becomes appreciable in a vacuum at 2000°C. Be2N2 is rapidly oxidized by air at 600°C and like the carbide is hydrolyzed by moisture. The oxide forms on beryllium metal in air at elevated temperatures, but in the absence of oxygen, beryllium reacts with nitrogen to form the nitride. When hot pressing mixtures of beryUium nitride and sUicon nitride, Si N, at 1700°C, beryllium sUicon nitride [12265-44-0], BeSiN2, is obtained. BeSiN2 may have appHcation as a ceramic material. 

Beryllium metal is relatively unreactive at room temperature, particularly in its massive form. It does not react with water or steam even... 

The early promise of wide applications for beryllium has not materialised, despite improvements in purity and more efficient means of consolidation such as isostatic hot pressing, because of the metal s toxicity, brittleness and cost. It is now chiefly of interest in the specialised fields of aerospace and nuclear applications. BrushWellman is currently the sole commercial primary producer of beryllium metal in the West. 

The situation in beryllium metal is more complex. We might expect all of the 2s molecular orbitals to be filled because beryllium has the electron configuration ls22s2. However, in a crystal of beryllium, the 2p MO band overlaps the 2s (Figure 5). This means that, once again, there are vacant MOs that differ only infinitesimally in energy from filled MOs below them. This is indeed the basic requirement for electron conductivity it is characteristic of all metals, including lithium and beryllium. 

In both lithium and beryllium metal, there are vecant MOs only slightly higher in energy than filled MOs. This is the basic requirement for metallic conductivity. 

Beryllium phthalocyanine (PcBe) can be obtained by heating a mixture of phthalonitrile and beryllium metal, which has to be activated beforehand by etching with dilute acid.58... 

Several preparative methods do not use elemental mixtures. Group IIA-Pt intermetallic compounds have been prepared by reacting platinum metal with the group-IIA oxide under hydrogen or ammonia at 900-1200 C. Beryllium metal reacts with neptunium fluoride under vacuum at 1100-1200°C to form BC 3Np. 

Larsen, F.K. and Hansen, N.K. (1984) Diffraction studies of the electron density distribution in beryllium metal, Acta Cryst., B40, 169-179. 

The theory described in the previous section is now applied to beryllium metal. Accurate low temperature data was taken from the paper of Larsen and Hansen [20]. (But note that in (20) I used the structure factors multiplied by 1000, as given in then-paper.) For the orthogonalisation, all nearest neighbours we included within the first shell. There were 12 atoms. A triple zeta basis set from Ref. [21] was used. There are 182 basis functions and 361 independent parameters in the wave function, whereas there are 58 experimental measurements. Figure 1 shows a plot of the x2 agreement statistic as a function of the parameter X for k = 0.2. Larger values of k caused... 

The gas-phase decomposition of beryllocenes has been examined for the doping of semiconductor materials and in the preparation of thin metal films. Molecular-beam expitaxy has been used with (MeC5H4)2Be to dope InP semiconductors only a small amount of carbon is found in the doped films.54 Beryllocene 9 has been explored as a precursor for coating capsules with beryllium metal for use as targets in experiments with inertial confinement fusion.55... 

Beryllium metal is used as a window material for X-ray tubes (it has 17 times the transmittance of aluminum). Notwithstanding the high cost of the metal, it has been tested for use in high-performance sports equipment such as golf clubs, bicycles, and motorcycles. 

Kjellgren A process for making beryllium by reducing beryllium fluoride with magnesium. Invented in 1941 by B. R. F. Kjellgren at the Brush Beryllium Company, OH, and now the principle commercial method for making beryllium metal. 

Another method for obtaining beryllium metal is by electrolysis of a solution of berylhum chloride (BeCy along with NaCl as an electrolyte in solution that is kept molten but below the melting point of beryllium. ( Be has a relatively high melting point of 2,332.4°F.) The beryllium metal does not collect at the negative cathode as do metals in other electrolytic cells, but rather beryllium metal pieces are found at the bottom of the cell at the end of the process. 

Beryllium chloride (BeClj) is used as a catalyst to accelerate many organic reactions, and beryllium chloride is the electrolyte used along with NaCl in the electrolytic process to produce beryllium metal. 

Beryllium fluoride (BeFj) is an example of beryllium that has an oxidation state of +2, combining with a negative anion element with an oxidation state of—1. BeryUiiun fluoride is also used along with magnesium metal in the chemical reduction process to produce beryllium metal. 

Uses. Beryllium metal sheet or wire ceramics hardening agent in alloys used especially in the electronics field... 

Beryllium metal, beryllium-aluminum alloy, beryl ore, beryllium chloride, beryllium fluoride, beryllium hydroxide, beryllium sulfate, and beryllium oxide all produce lung tumors in rats exposed by inhalation or intra-tracheally. The oxide and the sulfate produce lung tumors in monkeys after intrabronchial implantation or inhalation. A number of compounds produce osteosarcomas in rabbits after their intravenous or intramedullary administration. ... 

The reliable experimental information on the absolute scale and thermal vibrations of beryllium metal made it possible to analyze the effect of the model on the least-squares scale factor, and test for a possible expansion of the 1 s core electron shell. The 0.03 A y-ray structure factors were found to be 0.7% lower than the LH data, when the scale factor from a high-order refinement (sin 6/X) > 0.65 A l) is applied. Larsen and Hansen (1984) conclude that because of the delocalization of the valence electrons, it is doubtful that diffraction data from a metallic substance can be determined reliably by high-order refinement, even with very high sin 0/X cut-off values. This conclusion, while valid for the lighter main-group metals, may not fully apply to metals of the transition elements, which have much heavier cores and show more directional bonding. 

Beryllium fluoride is the intermediate compound in the magnesium-reduction process to produce beryllium metal. The compound also is used in the manufacture of glass, and in nuclear reactors. 

Beryllium nitride may be prepared by heating beryllium metal powder with dry nitrogen in an oxygen-free atmosphere above 700°C ... 

Beryllium (Glucinum) Fluoride, BeF2, mw 47 01, colorless, poisonous pdr, sp gr 2.0l at 15°, mp 800° bp — sublimes v sol in w sol in ale, acids and alkalies. Can be prepd by thermal decomph (at 900—950°) of ammonium beryllium fluoride. Used in production of beryllium metal by reduction with Mg metal Refs 1) Gmelin-Kraut System Number 26(1930), 105 2) Hackh sDict (1944), 123-R 3) Cond-... 

Figure 7.4 The 2s and 2p bands of beryllium metal before (left-hand side) and after (right-hand side) overlap is allowed to occur the red colouring indicates filled levels, the shading indicates vacant levels...

Table 7.2 Physical properties of lithium and beryllium metals...

Heating the ammonium beryllium carbonate solution to 95°C causes nearly quantitative precipitation of beryllium basic carbonate [66104-24-3], Be(OH)2 2BeC03. Evolved carbon dioxide and ammonia are recovered for recycle as the strip solution. Continued heating of the beryllium basic carbonate slurry to 165°C liberates the remaining carbon dioxide and the resulting beryllium hydroxide [13327-32-7] intermediate is recovered by filtration. The hydroxide is the basic raw material for processing into beryllium metal, copper—beryllium and other alloys, and beryllia [1304-56-9] for ceramic products. Approximately 90% of the beryllium content of bertrandite is recovered by this process. 

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