Sensitivity of Mild Hydrothermal Synthesis to the Reaction Conditions: Targeting Mixed-Metal Hexagonal Tungsten Bronze Fluorides MMF to Investigate Their Magnetic Behavior.

The synthesis of five quaternary hexagonal tungsten bronze (HTB) fluorides, MMF, ( = Cs and Rb; M = Co, Ni, and Zn; and = V) via a mild hydrothermal route is reported. The crystal structures and compositions were determined using a combination of single-crystal X-ray diffraction, Rietveld refinement of powder X-ray diffraction data, and inductively coupled plasma optical emission spectroscopy analysis. This study highlights the sensitivity of the mild hydrothermal method on the reaction temperature, solvent system, and quantity of starting reagents that directly influence the selective synthesis of kinetically stabilized fluoride materials, including hydrated fluorides, β-pyrochlores, and HTB.

Boron Chalcogen Mixture Method-Assisted Alkali Halide Flux Crystal Growth of an Extensive Family of Quaternary Rare Earth Transition-Metal Thiosilicates: Investigation of Their Structures and Magnetic Properties.

A series of transition-metal-containing rare earth thiosilicates, RETMSiS (RE = Gd-Yb; TM = Fe, Co, Ni), was obtained via flux crystal growth utilizing the boron chalcogen mixture (BCM) method. The series includes the first reported ytterbium-containing thiosilicates crystallizing in this structure type. The thiosilicates crystallize in the hexagonal crystal system in space group 6.

Synthesis, Characterization, and Magnetic Properties of Uranium-Containing 2H-Perovskite-Related Sulfides: BaMUS (M = Mn, Fe, Co, Ni) and BaCoMgUS.

The uranium-containing 2H-perovskite-related chalcogenide family of compounds was revisited using the recently developed boron-chalcogen mixture (BCM) method for actinides to aid in their syntheses and to obtain magnetic measurements. Two known 2H-perovskite-related structures, BaMnUS and BaFeUS, were synthesized using the BCM method and were found to exhibit antiferromagnetic transitions at = ∼7.6 and 10.

Crystal Structures and Property Measurements of Rare Earth Magnesium Thiosilicates Synthesized via Flux Crystal Growth Utilizing the Boron Chalcogen Mixture (BCM) Method.

Nine new rare earth magnesium-containing thiosilicates of the formula REMgSiS (Ln = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er) were synthesized in an alkali halide flux using the boron chalcogen mixture (BCM) method. Crystals of high quality were produced, and their structures were determined by single-crystal X-ray diffraction. The compounds crystallize in the hexagonal crystal system in the 6 space group.

Structures and Magnetic Properties of KPdUS, KPtUS, RbPtUS, and CsPtUS Synthesized Using the Boron-Chalcogen Mixture Method.

A series of AMUS (A = alkali metal; M = Pd, Pt) compounds, specifically KPdUS, KPtUS, RbPtUS, and CsPtUS, were synthesized using the combined boron-chalcogen mixture and molten flux crystal growth methods. The formation of rubidium- and cesium-containing analogues resulted from a alkali polysulfide flux formed from alkali carbonates. The successful synthesis of single crystals of the title compounds allowed for their structural characterization by single-crystal X-ray diffraction.

Lanthanide thioborates, an emerging class of nonlinear optical materials, efficiently synthesized using the boron-chalcogen mixture method.

The Boron-Chalcogen Mixture method was used to obtain single crystals of the previously extremely difficult to synthesize lanthanide orthothioborates to investigate their structures and their structurally connected optical behavior, such as second harmonic generation. Using a combined halide and polychalcogenide flux, the BCM method yielded single crystals of LnBS (Ln = La, Ce, Pr, Nd), which are isostructural and crystallize in the non-centrosymmetric space group, 2. Second harmonic generation measurements confirmed the expectation that LaBS would exhibit a strong SHG response, measured at 1.

Synthesis of Hydrated Ternary Lanthanide-Containing Chlorides Exhibiting X-ray Scintillation and Luminescence.

A series of new ternary lanthanide-based chlorides, CsEuCl(HO), CsLnCl(HO) (Ln = Gd or Ho), CsTbCl(HO)(HO), CsDyCl(HO), CsErCl(HO), and CsLnCl(HO) (Ln = Y, Lu, or Yb), were prepared as single crystals via a facile solution route. The compounds with compositions of CsLnCl(HO) (Ln = Gd or Ho) and CsLnCl(HO) (Ln = Y, Lu, or Yb) crystallize in a monoclinic crystal system in space groups 2 and 2/, respectively, whereas CsEuCl(HO), CsTbCl(HO)(HO), and CsErCl(HO) crystallize in orthorhombic space groups , , and 222, respectively. CsDyCl(HO) crystallizes with triclinic symmetry in space group 1̅.

Facile Oxide to Chalcogenide Conversion for Actinides Using the Boron-Chalcogen Mixture Method.

Actinide chalcogenides are of interest for fundamental studies of the behavior of 5f electrons in actinides located in a soft ligand coordination environment. As actinides exhibit an extremely high affinity for oxygen, the synthesis of phase-pure actinide chalcogenide materials free of oxide impurities is a great challenge and, moreover, requires the availability and use of oxygen-free starting materials. Herein, we report a new method, the boron-chalcogen mixture (BCM) method, for the synthesis of phase-pure uranium chalcogenides based on the use of a boron-chalcogen mixture, where boron functions as an "oxygen sponge" to remove oxygen from an oxide precursor and where the elemental chalcogen effects transformation of the oxide precursor into an oxygen-free chalcogenide reagent.

Nearly Identical but Not Isotypic: Influence of Lanthanide Contraction on CsNaLn(PS) (Ln = La-Nd, Sm, and Gd-Ho).

The effect of lanthanide contraction often results in topological and symmetry changes in compounds with the same compositions as a function of lanthanide cation size. Here we report on the first example of a lanthanide thiophosphate exhibiting a change in the lanthanide cation environment without any topological or symmetry change. A series of new lanthanide thiophosphates with mixed alkali cations were obtained via a flux crystal growth technique using a CsI flux.

Size-Driven Stability of Lanthanide Thiophosphates Grown from an Iodide Flux.

To determine the influence of the lanthanide size on the structures and properties of thiophosphates, a thiophosphate series containing different lanthanides was synthesized via high temperature flux crystal growth and their structures and physical properties analyzed and compared. Layered thiohypophosphates NaLnPS (Ln = La, Ce, Pr) and thiopyrophosphates CsLnPS (Ln = Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Yb, Y) were grown out of an iodide flux using consistent reaction conditions across both series. Under the mildly reducing iodide flux reaction conditions, a rather rare example of phosphorus reduction from the +5 to the +4 oxidation state was observed.