The crystal structure of R-phase in Ti-50.75.Ni-47.75.Fej.(50) shape memory alloy (SMA) has been studied at a temperature of (290 +/- 7) K on cooling by combined synchrotron and neutron powder diffraction using Rietveld refinement with generalized spherical harmonic (GSH) description for preferred orientation (PO). The results showed that (i) no significant improvement in the crystallographic R-WP-factor was found when the inversion center was removed from the P (3) over bar model, suggesting that the space group was indeed P (3) over bar and not lower symmetry P3 neither P31m and (ii) the refined atomic parameters were converging only when the P (3) over bar space group was used in the refinement.