Bases beryllium solutions

Only beryllium hydroxide dissolves appreciably in strong base solutions,... 

The oxides of metalloids and some of the less electropositive elements are amphoteric (react with both acids and bases). Aluminum oxide, for instance, reacts with acids and with alkalis (aqueous solutions of strong bases). The oxides reveal a strong diagonal relationship between beryllium and aluminum, because beryllium oxide is also amphoteric. 

Similarly, the cations that form strong bases (the alkali metals and the metals below beryllium in Group 2 (IIA)) do not tend to react with hydroxide ions. These cations are weaker acids than water. Therefore, when a salt contains one of these ions (for example, Na ) the cation has no effect on the pH of an aqueous solution. 

The coordination process may either stabilize or destabilize aromatic Schiff bases. If nickel (II) salts are added to ammoniacal solutions of salicylaldehyde, the precipitate obtained is the inner complex salt of nickel (II) and salicylaldimine (61). If beryllium chloride is added to the Schiff base derived from 2-hydroxy-l-naphthaldehyde and ethylamine, however, the Schiff base is decomposed and the inner complex of beryllium (II) and 2-hydroxy-1-naphthaldehyde is obtained (59). Here the strength of the coordinate bonds formed with the metal seems to determine which complex will be formed. 

Metallic elements with low ionization energies commonly form ionic oxides. As remarked in Section 10.1, the oxide ion is a strong base, so the oxides of most of these metals form basic solutions in water. Magnesium is an exception because its oxide, MgO, is insoluble in water. However, even this oxide reacts with acids, so it is regarded as basic. Elements with intermediate ionization energies, such as beryllium, boron, aluminum, and the metalloids, form amphoteric oxides. These oxides do not react with water, but they do dissolve in both acidic and basic solutions. 

Water-free inorganic solvents, such as ammonia, sulfur dioxide, and hydrazine, have been tested in terms of their suitability for electrolytic metal deposition. Liquid ammonia is used for a series of electrolytic metal deposition processes. Besides the low boiling point (- 33 °C) of this solvent its toxicity is disadvantageous. It has been reported that group lA and IIA metals, such as hthium, sodium, magnesium, and beryllium can be deposited from solutions based on ammonia as a solvent [45]. However, only thin or incoherent layers are thus produced [43, 44]. Because it is possible to form anions of molybdenum, lead, selenium, and tellmium in anunonia, these elements can be anodically deposited. Thus, deposition of the semiconductor lead selenide has also been achieved with ammonia as a solvent. 

Decrystallization of cellulose by swelling agents or solvents can be brought about by concentrated sodium hydroxide amines me-tallo-organic complexes of copper, cadmium, and iron quaternary ammonium bases concentrated mineral acids (sulfuric, hydrochloric, phosphoric) concentrated salt solutions (beryllium, calcium, lithium, zinc) and a number of recently investigated mixed solvents (J6). 

Beryllium does not react with pure water even at red heat. It reacts with solutions of strong bases to form the complex ion, [Be(OH)4] , and H2. Magnesium reacts with steam to produce MgO and H2. Ca, Sr, and Ba react with water at 25°C to form hydroxides and H2 (see Table 23-4). Group IIA compounds are generally less soluble in water than corresponding lA compounds, but many are quite soluble. 

Gibson s method 4 is based on the principle that ammonium hydrogen fluoride effects the complete decomposition of beryl at a low temperature, even if the mineral is only coarsely ground. Much of the silica is volatilized as ammonium fluosilicate and the beryllium and aluminium converted first to fluorides, then sulfates. The former is separated by solution in (NH COs. 

Selective, sensitive techniques based on gas chromatography or atomic absorption have been developed. The trifluoroacetylacetonate derivative of beryllium may be extracted from aqueous solutions into benzene and the beryllium determined by gas chromatography (9). Under optimum conditions 4 X 10 13 g can be detected with an electron capture detector (JO). With a mass spectroscopic detector the detectible quantity is 2.5 X 10 n g, but the specificity of the method is greatly improved (II). Flame atomic absorption has been used to determine beryllium in many materials (12). The technique can be used to measure levels down to 0.02 fig Be/ml in aqueous solutions. However, some interferences may be encountered even with the nitrous oxide-acetylene... 

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