Hydrides beryllium

The hydrides of beryllium and magnesium are both largely covalent, magnesium hydride having a rutile (p. 36) structure, while beryllium hydride forms an electron-deficient chain structure. The bonding in these metal hydrides is not simple and requires an explanation which goes beyond the scope of this book. 

Beryllium Hydride. BeryUium hydride [13597-97-2] is an amorphous, colorless, highly toxic polymeric soHd (H = 18.3%) that is stable to water but hydroly2ed by acid (8). It is insoluble in organic solvents but reacts with tertiary amines at 160°C to form stable adducts, eg, (R3N-BeH2 )2 (9). It is prepared by continuous thermal decomposition of a di-/-butylberylhum-ethyl ether complex in a boiling hydrocarbon (10). 

Beryllium hydride was formerly of interest as a rocket fuel and as a moderator for nuclear reactors. 

Although modern chemistry allows development of even more effective rocket propellants, energy efficiency is not the only consideration factor. For example, fluorine and its derivatives arc better oxidizers than oxygen, but their extreme toxicity make them environmentally dangerous. The same concerns prevent the use of beryllium hydride—an excellent fuel that combines high density with the energy efficiency comparable to liquid hydrogen. 

Barrier values of internal rotation, 381 Benzene photochemical studies, 200 Beryllium, hydride ion (BeH+) electron correlation, 324 ion (Be2f), 299... 

To achieve higher energy in solid proplnts the most notable advances were achieved with the addition of aluminum and beryllium to both double-base and composite proplnts. Energy in this case is commonly equated to high specific impulse. Later developments added aluminum hydride and beryllium hydride to this list. In Table 16, the specific impulse performance of proplnts using AP with various metals and hydrides is compared to those systems without these additives (Ref 43)... 

The beryllium hydride derivative [TpBut]BeH is obtained by metathesis of either [TpBut]BeCl or [TpBut]BeBr with LiAlH4 in Et20 at room temperature [Eq. (27)] (56). 

Zaluska, A., L. Zaluski, and J.O. Strom-Olsen, Lithium-beryllium hydrides The lightest reversible metal hydrides,. Alloys Compd., 307,157,2000. 

Beryllium hydride (BeH ) liberates hydrogen gas when mixed with water. It is used as a source of hydrogen in experimental rockets and fuel cells. 

Beryllium hydride has few commercial applications. It is used in rocket fuels. 

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

Beryllium hydride reacts with water, dilute acids, and methanol, liberating... 

Problem 8-6. What is the Schrodinger equation for Beryllium Hydride, BeH2 ... 

Compounds with H H—H Hydrogen H—Be—H Beryllium hydride H—B—H Boron hydride H 1 H—C—H 1, Methane H—N—H Ammonia H— H Water H—F Hydrogen fluoride... 

Similarly, high performance solid propellants consisting of Poly(GlyN) binder, ammonium perchlorate oxidizer and beryllium/beryllium hydride fuel which also do not require the presence of plasticizers and offer optimum performance at low solids loading have been reported for space launch vehicles [143]. 

Common synthetic routes to beryllium amides, which were summarized in Ref. 1, involve the direct or indirect amination of beryllium hydride, beryllium chloride, a beryllium alkyl or amide precursor. Beryllium amides with bulky substituents are generally synthesized via the trans-metallation of beryllium dichloride with the lithium amides. The reaction of beryllium dichloride with secondary amines in the presence of an alkyllithium represents a less common synthetic route to beryllium amides. The formation ofbery Ilium amides via the reaction of an alkyl beryllium as well as beryllium hydride species with amines is also known. ... 

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