Noncentrosymmetric (NCS) materials have attracted attention because of their broken inversion symmetry, leading to unconventional superconducting properties including spin singlet-triplet mixing and time-reversal-symmetry breaking. The compounds Re6Zr, Re6Hf, and Re3Ta are all NCS superconductors. Powder x-ray diffraction data collected on these materials indicate that the samples all form as a single phase, but the refined compositions are non-stoichiometric. There is interest in performing precise density functional theory calculations to determine the band structure of these materials, and group theory analysis of the superconducting states of these NCS systems. This theoretical work requires knowledge of the position of the atoms, site occupancies and vacancies within the structure of these compounds. We propose to measure the crystal structure using powder neutron diffraction.