Understanding the correlation between ionic motion and crystal structure is crucial for improving solid electrolyte conductivities. Several substitution series in the Li GeP S structure have shown a favorable impact on the ionic conductivity, the replacement of P(+V) by Sb(+V) in Li GeP S . However, here the interplay between the structure and ionic motion remains elusive. X-Ray diffraction, high-resolution neutron diffraction, Raman spectroscopy and potentionstatic impedance spectroscopy are employed to explore the impact of Sb(+V) on the Li GeP S structure. The introduction of antimony elongates the unit cell in the -direction and increases the M(1)/P(1) and Li(2) polyhedral volume. Over the solid solution range, the Li distribution remains similar, an inductive effect seems to be absent and the ionic conductivity is comparable for all compositions. The effect of introducing Sb(+V) in Li GeP S cannot be corroborated.