Sodium beryllate

Beryllium hydroxide is prepared by treating basic beryllium acetate, Be40(C2H302)e with caustic soda solution or by precipitation from a strongly alkaline solution of sodium beryllate. The precipitate is dried at 100°C. 

Write the equations of the reactions and explain the occurring-processes. What is the coordination number of beryllium in sodium beryllate What type of orbital hybridization occurs when the beryllate ion forms and what spatial configuration does this correspond to ... 

The beta modification is best prepared by slow hydrolysis of sodium beryllate. Boiling ION NaOH solution is saturated with pure, amorphous beryllium hydroxide until a permanent turbidity is just evident. A sandy, finely crystalline product separates tq)on slow cooling. Under the microscope, the crystals appear as beautiful, regular double pyramids. They may be purified, without changing their appearance, with warm water until they no longer show an alkaline reaction the crystals are then dried at 80°C. 

I. Concentrated sodliim hydroxide saturated with beryllium hydroxide, or alcoholic potassium hydroxide saturated with potassium beryllate, both prepared with exclusion of COg, is filtered in the presence of KOH through an asbestos filter in a silver funnel. The filtrate is vacuum-evaporated in a nickel dish in the presence of H3SO4 and KOH. The first precipitate consists of NagCOg and some Be(QH)g. As soon as the separation of the snow-white, shining sodium beryllate begins, the filtration is repeated and the solution further evaporated. The product is washed with alcohol and dried in a vacuum desiccator. 

In Fig. 9.13, the heat treatments are necessary to improve the efficiency of the sulphation step. The latter can be engineered in several alternative types of plant. Alternatives are available for the subsequent steps to pure oxide, but usually based upon precipitation and crystallization, as is the one shown in Fig. 9.13. The precipitation of beryllium hydroxide by boiling an alkaline solution of sodium beryllate, is a particularly valuable purification step, and is also used in Fig. 9.14. Chlorination of oxide mixed with carbon is a standard type of operation as used for the preparation of chloride intermediates of other metals. Molten salt electrolysis is one of the two alternative commercial routes to pure beryllium metal, the other being shown in Fig. 9.14. 

The commercial ores, beryl and bertrandite, are usually decomposed by fusion using sodium carbonate. The melt is dissolved in a mixture of sulfuric and hydrofluoric acids and the solution is evaporated to strong fumes to drive off siUcon tetrafluoride, diluted, then analy2ed by atomic absorption or plasma emission spectrometry. If sodium or siUcon are also to be determined, the ore may be fused with a mixture of lithium metaborate and lithium tetraborate, and the melt dissolved in nitric and hydrofluoric acids (17). 

Beryllium is extracted from the main source mineral, the alumino-silicate beryl, by conversion to the hydroxide and then through either the fluoride or the chloride to the final metal. If the fluoride is used, it is reduced to beryllium by magnesium by a Kroll-type reaction. The raw metal takes the form of pebble and contains much residual halides and magnesium. With the chloride on the other hand, the pure metal is extracted by electrolysis of a mixture of fused beryllium chloride and sodium chloride. The raw beryllium is now dendritic in character, but still contains residual chloride. 

Beryllium, at the head of Group 2, resembles its diagonal neighbor aluminum in its chemical properties. It is the least metallic element of the group, and many of its compounds have properties commonly attributed to covalent bonding. Beryllium is amphoteric and reacts with both acids and alkalis. Like aluminum, beryllium reacts with water in the presence of sodium hydroxide the products are the beryl-late ion, Be(OH)42, and hydrogen ... 

In Table XVIII are given values of the radius ratio for the salts of beryllium, magnesium and calcium (those of barium and strontium, with the sodium chloride structure, also obviously satisfy the radius ratio criterion). It is seen that all of the sodium chloride type crystals containing eight-shell cations have radius ratios greater than the limit 0.33, and the beryl-... 

Fluoridizing roasting or fluorination is similar to chlorination, and is widely used in the treatment of several rare metal ores. Beryl, the most important ore of beryllium, can be opened by fusing with sodium silicofluoride at 850 °C ... 

Copaux A method for extracting beryllium from beryl. The ore is heated with sodium flu-orosilicate at 850°C. Leaching with water dissolves the beryllium fluoride, leaving the silica and most of the aluminum fluoride as an insoluble residue. Addition of sodium hydroxide precipitates beryllium as the hydroxide. The process was invented by H. Copaux and has been in use in France since 1915 and in the United Kingdom since World War II. 

Copaux-Kawecki An improved version of the Copaux process for extracting beryllium from beryl, which permits recovery of the fluorine. Addition of ferric sulfate to the dilute sodium fluoride solution remaining after the separation of the beryllium hydroxide precipitates sodium tetrafluoroferrate, which is then used in place of sodium fluorosilicate. 

Metallic beryllium is produced by reduction of beryllium halide with sodium, potassium or magnesium. Commercially, it is obtained primarily from its ore, beryl. Beryllium oxide is separated from silica and alumina in ore by melting the ore, quenching the solid solution, and solubilizing in sulfuric acid at high temperatures and pressure. Silica and alumina are removed by pH adjustment. Beryllium is converted to its hydroxide. Alternatively, beryl is roasted with complex fluoride. The products are dissolved in water and then pH is adjusted to produce beryllium hydroxide. 

Sodium hydroxide solution white gelatinous precipitate of beryllium hydroxide, readily soluble in excess of the precipitant, forming tetrahydroxo-beryllate ion, [Be(OH)4]2 on boiling the latter solution (best when largely diluted), beryllium hydroxide is reprecipitated (distinction from aluminium). The precipitate is also soluble in 10 per cent sodium hydrogen carbonate solution (distinction from aluminium). 

The most important mineral is beryl, Be3Al2(Si03)6, which often occurs as large hexagonal prisms. The extraction from ores is complicated.5 The metal is obtained by electrolysis of BeCl2 but, since the melt has very low electrical conductivity (about 10-3 that of NaCl), sodium chloride is also added. 

Often the Si—O—Si—O— links form rings or sheets instead of chains. In the mineral benitoite, rings are closed by three SiO groups, and each ring is accompanied by a barium ion and a titanium ion. In beryl a ring of six SiO groups accommodates three beryllium ions and two aluminum ions. Just as in sodium chloride, it is impossible to identify molecular units in these minerals one can identify only ionic units. 

II. Monosodium beryllate and Be (OH) 3 exist as the solid-phase components in the system BeO-NaOH-HgO at 30°C, when the concentrations of NaOH and BeOH are about 33% and 4.3%, respectively at higher sodium hydroxide concentrations, monosodium beryllate is the only solid-phase component. 

Beryllium is amphoteric forming beryl-late species, such as [Be(OH)4] and [Be(OH)]3. The hydroxide is only weakly basic. The element does not form a true carbonate the basic beryllium carbonate, BeC03.Be(0H)2 is formed when sodium carbonate is added to solutions of beryllium compounds. 

Figure 86 Beryl, cyclosilicate ions and Na ions. The 6-coordination of the sodium to the shared oxygens in the 6-membered tings is shown. The unit cell is shown with lines connecting the sodium ions.

Preparation from Beryl.—Since beryl is not directly attacked by any acid, except, perhaps, by hydrofluoric when ground to a dust, it must first be fused with some flux or be heated in the electric furnace to a temperature (Lebeau, 1895 5) which volatilizes some of the silica and leaves a residue easily attacked by hydrofluoric acid. For those having the facilities, this latter method presents many advantages. Among the fluxes whicl can be successfully used are sodium and potassium carbonates, calcium fluoride, potassium fluoride, calcium oxide, and sodium and potassium hydroxide. The fluorides possess the advantage in subsequent treatment, in the comparative ease of removal of the large... 

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