Synthesis and Crystal Structure of the Layered Lanthanide Oxychlorides Ba3Ln2O5Cl2
Single crystals of a new family of layered lanthanide oxychlorides, Ba3Ln2O5Cl2 (Ln = Gd-Lu), have been synthesized from a molten barium flux. This family crystallizes in the space group I4/mmm (No. 139; Z = 2) with lattice parameters a = 4.3384(1)-4.4541(1) Å and c = 24.5108(7)-24.8448(9) Å. Ba3Ln2O5Cl2 phases are built up of two different blocks: a perovskite double layer of stoichiometry Ba2Ln2O5 formed by corner-connected LnO5 tetragonal bipyramids and a puckered rock-salt-like interlayer of composition BaCl2. A complete structural study along with bond-valence-sum calculations shows that, for lanthanides larger than gadolinium, the structure becomes unstable. Density functional theory calculations show that the valence-band edge is dominated by oxygen orbitals, whereas the conduction band forms from Ba 5d orbitals. The synthesis of this family suggests a route to other potential multianion phases.
layers, magnetic properties, oxygen, lanthanides, perovskites
Besara, Tiglet, Daniel C. Ramirez, Jifeng Sun, Nathaniel W. Falb, Wangwei Lan, Jennifer N. Neu, Jeffrey B. Whalen, David J. Singh, and Theo Siegrist. "Synthesis and crystal structure of the layered lanthanide oxychlorides Ba3Ln2O5Cl2." Inorganic chemistry 57, no. 4 (2018): 1727-1734.