C24H33CINO5P , M r = 481.95, orthorhombic, P2~2121, a=8.026(2), b= 16.103 (6), c = 19.169 (5) A, V= 2478 (2) A 3, z = 4, O x = 1.29gem -3, CuKa radiation, 2= 1.54184A, g= 22.73 cm -~, F(000) = 1024, R = 0.037, wR = 0.037 for 3596 observed reflections and 391 variables. The structure was solved by automatic application of the vector-search orientation function and the DIRDIF structure expansion procedure. The structure contains phosphorinane anions and ephedrine cations which are linked in a three-dimensional network by N-H...O and O-H...O hydrogen bonds. The phosphorinane ring is in the chair conformation. The ephedrine is in the usual extended form. The structure of a diastereoisomer is reported by Kok, Wynberg, Garcia-Granda, Beurskens & Smit [Acta Cryst. (1988), C44, 2235-2237].