Addition of methyl lithium to d-erythrono-1,4-lactone followed by acid deprotection was shown, by X-ray crystallography, to give 1-de-oxy-d-arabinitol, C(5)H(12)O(4), rather than 1-de-oxy-d-ribitol as the major product. The crystal structure exists as hydrogen-bonded chains of mol-ecules running parallel to the c axis which are further linked together by hydrogen bonds. Each mol-ecule is a donor and an acceptor for four hydrogen bonds.