New layered perovskite compounds Ca2FeMnO6 and Ca2FeMnO5.5 were recently synthesized. Ca2FeMnO6 was obtained by low-temperature topotactic oxidation of brownmillerite-type Ca2FeMnO5 with layered Fe/Mn ordering. Ca2FeMnO5.5 was obtained by heating either Ca2FeMnO6 or Ca2FeMnO5.5 in air at 250-300 °C. The oxidation states of Fe/Mn are expected to vary as Ca2Fe3+Mn3+O5/ Ca2Fe3+Mn4+O5.5 / Ca2Fe4+Mn4+O6. The orderings of the B-site cations and oxygen vacancies in these compounds are of primary interest. It is also important to confirm the various valence states of Fe and Mn at the B sites. We request 4 days on WISH to follow the low-temperature evolution of the crystal structure and magnetic order in the new d = 0 and 0.5 materials and to compare with the δ = 1.0 parent. A standard 4-300 K CCR will be sufficient to record diffraction patterns of Ca2FeMnO6-d (d = 0, 0.5, 1.0).