The complex hydrides. NaR,BeH (R = Prn, Pr', and Bu') are described, together with Li(OEt,)Bu*,BeH, LiBu',-BeH, Na(OEt,),But4Be2H. and Na(OMe,)Et,BeH.Pyrolysis of the isopropyl and of the butyl salts in the range 60-200" results in elimination of olefin and of some dialkyl, R,Be, to leave a residue of sodium beryllium hydrides the composition of which depends on the pyrolysis conditions.Sodium di-isobutylberyllium hydride, which is insoluble in hydrocarbons, dissolves in solutions of di-isobutylberyllium in hexane up to a limit corresponding to the composition Na,Bui qBe,H,. Sodium diethylberyllium hydride combines with diethylberyllium to give a product, NaEt6Be,H, which I S insoluble in hexane. Pyrolysis of this salt gives NaEt,BeH.Di-isobutylberyllium may conveniently be characterized as its bispyridine adduct.ALKALI-METAL dimethyl-and diethyl-beryllium hydrides were first described several years ago and their reactions with beryllium chloride have been used for the preparation of co-ordination complexes of methyl-and ethyl-beryllium hydride,, and the alkali-metal beryllium hydridesJ3 M,BeH,. Since the pyrolysis of the branched- But (ref. 5) , andBui (ref.6)] results in olefin elimination with formation of various beryllium hydrides, we have prepared several branched-chain alkali-metal dialkylberyllium hydrides and have studied their thermal decomposition to alkalimetal beryllium hydrides. For simplicity the formulae of alkali-metal alkylberyllium hydrides are written
