Lower purity material prepd by treating dimethylberyllium with LiAlH4 in ether: Barbaras et al., J. Am. Chem. Soc. 73, 4585 (1951); higher purity by pyrolysis of di-tert-butylberyllium: Coates, Glocking, J. Chem. Soc. 1954, 2526; Head et al., J. Am. Chem. Soc. 79, 3687 (1957); from triphenyl phosphine and beryllium borohydride: Banford, Coates, J. Chem. Soc. 1964, 5591.