The clathrate compounds of (S)-1, 1'-binaphthyl-2, 2'-diyl-(R)-α- methylbenzyl phosphor-amidate were synthesized and the crystal structure of ethanol clathrate compound was determined by X-Ray single crystal diffraction techniques. The structure was solved by the SHELXTL programme and Fourier techniques and refined by full-matrix least square to give a final R=0.0469 for 1640 observed reflection. The crystal belongs to monoclinic system with space group P2~1. The unit cell parameters are: a=0.9365(1)nm, b=1.2825(7)nm, c=1.1640(3)nm; β=111.71°, Z=2, Dx=1.27g/cm^3. The molecules of ethanol and phosphoramidate are connected each other by the force of hydrogen bond to form the layer structure.

Key words: X-RAY DIFFRACTION ANALYSIS, CLATHRATES, CRYSTAL STRUCTURE