Of beryllium borohydride

Beryllium hydride is made by treating an ethereal solution of beryllium borohydride with triphenylphosphine, or by pyrolysis of di-tert-butylberylh-um. 

Beryllium acetate has been found to give complexes of the type Be(OAc)2-2L with ammonia and primary amines, and beryllium borohydride forms 1 1 complexes with primary amines.101 IR studies on the complex Be(C104)2-2H20 show it to be in the form [Be(H20)4]2+[Be(C104)4]2 at elevated temperatures Be40(C104)6 is formed from the dihydrate.102... 

Beryllium borohydride reacts with triethylamine to give the compound Be(BH4)2N(GH3)3. The structure of this compound is not fully understood, but may be represented by... 

White solid. Higher purity material is inert to laboratory air. Loss of hydrogen at 190-200 negligible, rapid at 220. Reacts slowly with water, rapidly with dil acids. Insol in etbet, toluene, isopentane. Reacts with diborane to form beryllium borohydride. 

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 discussion above was limited to alanates, borohydrides, amides, and combinations of these materials. Other hydrides or alternative approaches have also been proposed for storage applications. Zaluska et al. ° studied lightweight lithium-beryllium hydride and showed a reversible hydrogen capacity of over 8 wt%. They also showed that the hydride may be usable down to 150°C. Although these results are rather promising, it is unlikely that any beryllium-containing compound would be considered for vehicular use because of the toxicity of this element, even though the hydride may be quite stable. 

Beryllium, aluminium and some transition metals such as thorium differ from the alkali metals in forming volatile borohydrides which constitute the most volatile compounds of these elements. On pyrolysis they decompose giving hydrogen and non-volatile residues. Electron diffraction and infrared studies suggest they possess bridge structures. 

Preparation of the first borohydrides, those of aluminum, beryllium, and lithium, by Schlesinger, H. C. Brown, Burg, and Sanderson (Ifi, 106, 114, 116), suggested the existence of similar compounds of other elements. This field was rapidly extended by studies related to the search for solid sources of hydrogen gas, volatile uranium compounds, and new methods for preparing diborane (107). 

All elements that form isochains can also form heterochains with other elements. In addition, simple heterochains can sometimes be formed by the next higher row of the periods III, IVB, and VB, namely aluminum, iron, and bismuth. Compounds with multicenter bonds are also formed by beryllium and a few elements from higher rows, e.g., niobium and vanadium. In these compounds, as well as the OH and H groups, the elements of period VIIB can also occur as the central atoms in multicenter bridge bonding, that is, in borohydrides, niobium iodide, etc. These elements, however, do not represent true chain atoms. 

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