ChemInform Abstract: Structural Studies of the Phases in Ba₂LaIrO₆ — New Light on an Old Problem.

Abstract

.-The title compound and La2ZnIrO6 are prepared by solid state reaction of stoichiometric mixtures of BaCO3, La2O3 or ZnO, and Ir (alumina crucibles, 1200°C, 6 d). Synchrotron X-ray and neutron powder diffraction profiles of Ba2LaIrO6 indicate that this compound crystallizes in the monoclinic space group I2/m at room temperature. A transition to a rhombohedral phase (space group R3) occurs upon heating to 375 K. Further heating results in the loss of the tilting of the octahedra leading to a Fm3m structure. Cooling to 100 K induces an additional phase transition to a triclinic structure (space group I1). -(ZHOU, Q.; KENNEDY*, B. J.; AVDEEV, M.; GIACHINI, L.; KIMPTON, J. A.; J. Solid State