A method for the regeneration of sodium borohydride from its hydrolysis product, sodium borate, is described. The dried borate salt was converted to a series of sodium tetraalkoxyborates prior to reaction with NaAlH(4) in refluxing diglyme to regenerate sodium borohydride. At room temperature in tetrahydrofuran, the same reactants formed the partial hydrides NaBH(3)(OR) (R = C1-4 alkyl). Products were characterised by multinuclear (1)H, (13)C, (11)B and (27)Al NMR studies. The intermediate alkoxyborate products were confirmed by single crystal X-ray structural studies. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.