Structural and Magnetic Characterization of La2NiRhO6

A polycrystalline sample of the perovskite La2NiRhO6 has been prepared. Neutron diffraction shows the compound to be orthorhombic (space group Pbnm; a=5.5350(4), b=5.5529(4), and c=7.8305(5) ? at 5 K) with a disordered arrangement of Ni and Rh over the six-coordinate B sites. Consideration of the B–O bond lengths and the paramagnetic Curie constant suggests that the Ni and Rh cations are trivalent and low spin. Magnetization and neutron diffraction experiments show that a transition to a spin-glass phase occurs upon cooling below 12 K.