Structural Investigations of Complex Oxides using Synchrotron Radiation

The work is a collaborative effort between Prof. Hanno zur Loye at the University of South Carolina and Dr. Tom Vogt at Brookhaven National Laboratory. The collaborative research focuses on the synthesis and the structural characterization of perovskites and perovskite related oxides and will target new oxide systems where we have demonstrated expertise in synthesis, yet lack the experimental capabilities to answer important structural issues. Synthetically, we will focus on two subgroups of perovskite structures, the double and triple perovskites, and the 2H-perovskite related oxides belonging to the A3n+3mA’nB3m+nO9m+6n family. In the first part of the proposal, our goal of synthesizing and structurally characterizing new ruthenium, iridium, rhodium and ruthenium containing double and triple perovskites, with the emphasis on exercising control over the oxidation state(s) of the metals, is described. These oxides will be of interest for their electronic and magnetic properties that will be investigated as well

Sr\u3csub\u3e3\u3c/sub\u3eMgPtO\u3csub\u3e6\u3c/sub\u3e

Single crystals of the mixed alkaline earth platinate, tristrontium magnesium platinum hexaoxide, Sr3MgPtO6, were grown from a KOH flux at 1273 K. The compound adopts the rhombohedral K4CdCl6 structure type, featuring chains of face-shared, distorted MgO6 trigonal prisms (Mg site symmetry 32) and PtO6 octahedra (Pt site symmetry ) surrounded by columns of Sr2+ ions (Sr site symmetry 2)

Sr\u3csub\u3e3\u3c/sub\u3eZnPtO\u3csub\u3e6\u3c/sub\u3e and Sr\u3csub\u3e3\u3c/sub\u3eCdPtO\u3csub\u3e6\u3c/sub\u3e

The flux synthesis of single crystals of the isostructural compounds tristrontium zinc platinum hexaoxide, Sr3ZnPtO6, and tristrontium cadmium platinum hexaoxide, Sr3CdPtO6, is reported. The compounds adopt the pseudo-one-dimensional rhombohedral K4CdCl6 structure type, and feature chains of face-shared distorted ZnO6 or CdO6 trigonal prisms and PtO6 octahedra, surrounded by columns of Sr2+ ions. All transition metals are located on the threefold axis of symmetry, while the Sr2+ cations lie on twofold axes. Formula: Sr3ZnPtO6 and Sr3CdPtO

Two different one-dimensional structural motifs in the same coordination polymer: a novel interpenetration of infinite ladders by bundles of infinite chains

A coordination polymer with a novel structural motifconsisting of stacks of infinite ladders interpenetrated bybundles of infinite chains is described; geometrical argumentsare made for the requirements that can lead to suchinterpenetration as a function of ligand dimensions

“[Cu(pyrazine-2-carboxylate)\u3csub\u3e2\u3c/sub\u3e]\u3csub\u3e2\u3c/sub\u3eCd\u3csub\u3e4\u3c/sub\u3eI\u3csub\u3e8\u3c/sub\u3e: Unprecedented 1-D serpentine chains and regular 2-D regular metal-organic square grids in a 3-D framework.

A novel three-dimensional coordination polymer containingan unprecedented one-dimensional serpentine motif conjoinedwith a two-dimensional square grid motif is presented

Ca\u3csub\u3e4\u3c/sub\u3eIrO\u3csub\u3e6\u3c/sub\u3e, Ca\u3csub\u3e3\u3c/sub\u3eMgIrO\u3csub\u3e6\u3c/sub\u3e and Ca\u3csub\u3e3\u3c/sub\u3eZnIrO\u3csub\u3e6\u3c/sub\u3e

Single crystals of tetracalcium iridium hexaoxide, Ca4IrO6, tricalcium magnesium iridium hexaoxide, Ca3MgIrO6, and tricalcium zinc iridium hexaoxide, Ca3ZnIrO6, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The three compounds are isostructural and adopt the K4CdCl6 structure type, comprised of chains of alternating face-shared [CaO6], [MgO6] or [ZnO6] trigonal prisms and [IrO6] octahedra, surrounded by columns of Ca2+ ions. Formula: Ca4IrO6, Ca3.34Mg0.66IrO6 and Ca3.50Zn0.50IrO

Crystal growth, Structure Determination and Magnetism of a New Hexagonal Rhodate: Ba9Rh8O24

Single crystals of Ba9Rh8O24, grown from a molten potassium carbonate flux, crystallize in the spacegroup R¯3c with lattice parameters of a = 10.0899(4) and c = 41.462(2) Å. Magnetic measurements on oriented single crystals reveal the existence of magnetic anisotrop

Trisodium Dicalcium Bismuth Hexaoxide

Single crystals of the title compound, Na3Ca2BiO6, were grown from a high-temperature reactive flux solution of Na2CO3. Na3Ca2BiO6 crystallizes as an ordered rock-salt structure (space group Fddd), in which the octahedral holes in the oxide array are filled by an ordered 3:2:1 arrangement of Na+, Ca2+ and Bi5+ cations. All atoms except for one O atom lie on special positions; site symmetries are as follows: Bi 222, Ca 2, Na 222 and 2, O 2

Bis[μ-1,2-bis(2-pyridyl)ethyne-\u3csub\u3eK\u3c/sub\u3e\u3csup\u3e2\u3c/sup\u3eN:N\u27]bis[aquadinitratocadmium(II)]

Two twisted 1,2-bis(2-pyridyl)ethyne ligands bridge two Cd2+ centers in the C2-symmetric title complex, [Cd2(NO3)4(-C12H8N2)2(H2O)2]. The bridging ligands arch across one another creating a `zigzag loop\u27 molecular geometry. Two nitrate ions and a water molecule complete the irregular seven-coordinate Cd-atom environment. The dihedral angles between the equivalent pyridyl ring planes of the two independent ligands are 67.2 (1)°. Owater-HOnitrate hydrogen bonding creates two-dimensional layers parallel to the ab plane. Formula: [Cd2(NO3)4(C12H8N2)2(H2O)2

Diaquabis(5-fluoro-2-hydroxybenzoato-κO\u3csup\u3e1\u3c/sup\u3e)zinc(II)

The title compound, [Zn(C7H4FO3)2(H2O)2], is a monomeric ZnII complex. The ZnII atom, which lies on a twofold rotation axis, is situated in a distorted tetrahedral environment composed of two monodentate carboxlyate O atoms and two water O atoms. O-HO hydrogen bonds link these units, forming sheets that are stacked along the c axis