ChemInform Abstract: A Family of Rare Earth Molybdenum Bronzes: Oxides Consisting of Periodic Arrays of Interacting Magnetic Units.

Abstract

A Family of Rare Earth Molybdenum Bronzes: Oxides Consisting of PeriodicArrays of Interacting Magnetic Units. -The compounds LnMo 16O44 (Ln: Y, La-Lu) are synthesized from stoichiometric mixtures of Ln 2O3, Mo, and MoO3 (silica tubes, 700 C, 5 d) and characterized by powder and single crystal XRD, magnetic measurements, and DFT electronic structure calculations. All the compounds crystallize in the rhombohedral space group R3. The structure contains two types of distinct layers built from corner-sharing MoO 6 octahedra and corner-sharing MoO4 tetrahedra, enclosing eight-coordinate Ln ions. The structure of LnMo16O44 is distinguished by the presence of isolated Mo 8O36 units of ReO3-type, that are entirely surrounded by MoO4 tetrahedra. The La, Ce, Pr, and Gd compounds display paramagnetic behavior with weak antiferromagnetic interactions between the lanthanoids. The d-orbital occupation in a unique Mo 8O36 structural subunit leads to a magnetic transition at temperatures around 6.5 K. -(SCHNEEMEYER, L. F.; SIEGRIST*, T.; BESARA, T.; LUNDBERG, M.; SUN, J.; SINGH, D. J.; J. Solid State Chem. 227 (2015) 178-185, http://dx.