Triply Ordered 6H Halide Perovskites: A Family of Triangular Lattice Antiferromagnets.

Three new hexagonal perovskites with CsMMRhCl (M = Na, Ag; M = Mn, Fe) stoichiometry have been synthesized from solution precipitation reactions. These air-stable compounds crystallize as triply cation-ordered variants of the 6H perovskite structure. This structure contains octahedra that share a common face to form MRhCl dimers that are arranged on a two-dimensional triangular network.

Anatomic Approach to Fetal Hydrocephalus.

Hydrocephalus is an imprecise term and refers to the imbalance of brain parenchyma and cerebral spinal fluid in the cranial vault. Ventriculomegaly, or enlargement of the ventricular system, is often the more precise term and is therefore preferred. Appropriate imaging and measurement techniques are critical to detect ventriculomegaly and grade its severity.

Pseudosymmetry in Tetragonal Perovskite SrIrO Synthesized under High Pressure.

In this study, we report a tetragonal perovskite structure of SrIrO (4/, = 3.9362(9) Å, = 7.880(3) Å) synthesized at 6 GPa and 1400 °C, employing the ambient pressure monoclinic SrIrO with distorted 6 structure as a precursor.

Origin of Magnetism in a Supposedly Nonmagnetic Osmium Oxide.

A supposedly nonmagnetic 5d^{1} double perovskite oxide is investigated by a combination of spectroscopic and theoretical methods, namely, resonant inelastic x-ray scattering, x-ray absorption spectroscopy, magnetic circular dichroism, and multiplet ligand-field calculations. We found that the large spin-orbit coupling admixes the 5d t_{2g} and e_{g} orbitals, covalency raises the 5d population well above the nominal value, and the local symmetry is lower than O_{h}. The obtained electronic interactions account for the finite magnetic moment of Os in this compound and, in general, of 5d^{1} ions.

Chiral Templating in a Hybrid Chromium Chloride Hydrate.

The synthesis and characterization of three new hybrid metal halide hydrates in which -[CrCl(HO)] cocrystallizes alongside α-methylbenzylammonium chloride are described. The enantiomorphic crystals, (()-(+)-α-methylbenzylammonium)(-[CrCl(HO)])Cl (()-) and (()-(-)-α-methylbenzylammonium)(-[CrCl(HO)])Cl (()-), have 222 space group symmetry and show mirrored circular dichroism signals. The racemate, (-α-methylbenzylammonium)(-[CrCl(HO)])Cl (()-), adopts a polar structure with space group symmetry in which enantiomers are related by mirror planes within organic bilayers.