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Date: 26-2-2019
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Date: 3-1-2017
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Date: 23-8-2016
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Aluminium hydride
Aluminium hydride can be prepared by below reaction the solvent can be Et2O, but the formation of etherate complexes ) Et2O(nAlH3 complicates the synthesis.
Above 423 K, [AlH3]n is unstable with respect to decomposition to the elements, and this thermal instability has potential for generating thin films of Al. Aluminium hydride reacts with Lewis bases, e.g. to give Me3N.AlH3 in which the Al centre is tetrahedrally coordinated. As is general among the p-block elements, later elements in a group may exhibit higher coordination numbers than earlier congeners, and one example is THF.AlH3, the solid state structure of which is dimeric, albeit with asymmetrical Al_H_Al bridges (Figure 1.1a).
Despite reports in the 1950s to the contrary, it now seems unlikely that InH3 and TlH3 have been prepared. A contributing factor to this is that the In_H (225 kJ mol_1) and Tl_H (180 kJ mol_1) mean bond enthalpies are significantly less than those of B_H (373 kJ mol_1), Al_H (287 kJ mol_1) and Ga_H (260 kJ mol_1).
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