The average and local structures in the (Ti 0:45 Cr 0:35 Mo 0:20 )-D system have been investigated by neutron powder diffraction and total neutron scattering. From the result of neutron powder diffraction, the crystal structure of the system was found to change from CaF 2 -type structure to bcc structure in the hydrogen desorption process, and the D atoms occupy the tetrahedral (T) sites in both CaF 2 -type and bcc phases.