Spin chirality on a two-dimensional frustrated lattice.

The collective behaviour of interacting magnetic moments can be strongly influenced by the topology of the underlying lattice. In geometrically frustrated spin systems, interesting chiral correlations may develop that are related to the spin arrangement on triangular plaquettes. We report a study of the spin chirality on a two-dimensional geometrically frustrated lattice.

Spin frustration in 2D kagomé lattices: a problem for inorganic synthetic chemistry.

A kagomé antiferromagnet presents an ideal construct for studying the unusual physics that result from the placement of magnetically frustrated spins on a low-dimensional lattice. Jarosites are the prototype for a spin-frustrated magnetic structure, because these materials are composed exclusively of kagomé layers. Notwithstanding, jarosite-type materials have escaped precise magnetic characterization over the past three decades, because they are notoriously difficult to prepare in pure and single-crystal forms.

Magnetic properties of a homologous series of vanadium jarosite compounds.

Redox-based, hydrothermal synthetic methodologies have enabled the preparation of a new series of stoichiometrically pure jarosites of the formula, AV(3)(OH)(6)(SO(4))(2) with A = Na(+), K(+), Rb(+), Tl(+), and NH(4)(+). These jarosites represent the first instance of strong ferromagnetism within a Kagomé layered framework. The exchange interaction, which is invariant to the nature of the A(+) ion (theta(CW) approximately equal to +53(1) K), propagates along the d(2) magnetic sites of the triangular Kagomé lattice through bridging hydroxyl groups.

Hydrothermal oxidation-reduction methods for the preparation of pure and single crystalline alunites: synthesis and characterization of a new series of vanadium jarosites.

Three new redox-based, hydrothermal, synthetic methods have been developed for the preparation of a new series of jarosites, AV(3)(OH)(6)(SO(4))(2) (A = Na(+), K(+), Rb(+), Tl(+), and NH(4)(+)), in high purity and in single crystalline form. The V(3+) jarosites have been characterized by single-crystal X-ray and elemental analysis, and by infrared and electronic absorption spectroscopy. The synthetic methods employed here represent a new approach for the preparation of the jarosite class of compounds, which for the past several decades, have been notoriously difficult to prepare in pure form.

Syntheses and Crystal Structures of a Linear-Chain Uranyl Phenylphosphinate UO(2)(O(2)PHC(6)H(5))(2) and Layered Uranyl Methylphosphonate UO(2)(O(3)PCH(3)).

Two extended uranyl organophosphorus compounds have been synthesized and structurally characterized. Linear-chain uranyl bis(phenylphosphinate), UO(2)(O(2)PHC(6)H(5))(2), was synthesized at 60 degrees C, and its structure was solved by single-crystal methods. UO(2)(O(2)PHC(6)H(5))(2) crystallizes in the triclinic space group P&onemacr; with unit cell parameters a = 5.

NaV (OH) (SO ) : A Kagomé-Type Vanadium(III) Compound with Strong Intralayer Ferromagnetic Interactions.

A dominant ferromagnetic exchange interaction propagates about the magnetic sites of the Kagomé lattice of the title compound through the bridging hydroxy groups (see section of the structure). This is at variance with the antiferromagnetic exchange observed for jarosite and its derivatives. The ferromagnetism probably arises from the d electron count of the V centers.

Intercalative Ion Exchange of Polyamine Transition Metal Complexes into Hydrogen Uranyl Phosphate.

A series of derivatives of hydrogen uranyl phosphate (HUP) was prepared by displacing the butylammonium ions of butylammonium uranyl phosphate with the transition metal complexes Cu(en)(2)(2+), Cu(pn)(2)(2+), Cu(trien)(2+), Cu(14-ane)(2+), Cu(15-ane)(2+), Ni(trien)(2+), Ni(14-ane)(2+), and Ni(diene)(2+). X-ray powder patterns proved that the original tetragonal structure of the UP layers remained intact in all derivatives. The extent of the ion exchange and the interlamellar distances were found to depend mainly on the size and on the shape of a particular coordinating ligand.