In recent years there has been a growing interest in modifying the anion lattice of complex transition metal oxides, via topochemical manipulation, to tune the magnetic and electronic properties of these materials. These processes not only alter the electron count of the phase but also the local symmetry and coordination geometry of the transition metal centres. We have utilized low temperature topochemical anion deintercalation reactions to reduce a series of rhodium-containing Ruddlesden-Popper oxides, to yield the first extended oxide phases to contain Rh(I) centres. We propose to collect neutron powder diffraction data to determine the crystal structures of the reduced compounds and the nature of the magnetic ordering present at low temperature.