Iridium oxides are of interest because many novel magnetic phases have been predicted in crystals, depending on the geometry of the crystal lattice. Our proposal concerns two such iridium oxides, both having a crystal structure known as the pyrochlore structure, in which the Ir ions form networks of connected tetrahedra. Our aim is to use neutron diffraction to determine the magnetic structures that occurs in these materials below 140 K. One possible type of order has the iridium magnetic moments pointing either all in or all out of the tetrahedral, and if this is present then it is possible that iridates in this family could exhibit a novel topological phase called a Weyl semi-metal.