A Noncentrosymmetric Polymorph of LuRuGe.

We report a new polymorph of LuRuGe, obtained in indium flux. This phase exhibits the noncentrosymmetric ZrNiAl-type structure with the space group 6̅2 as determined by single-crystal X-ray diffraction. This polymorph can convert into another centrosymmetric polymorph (TiNiSi-type structure, space group ) at high temperatures.

Local Orthorhombicity in the Magnetic C_{4} Phase of the Hole-Doped Iron-Arsenide Superconductor Sr_{1-x}Na_{x}Fe_{2}As_{2}.

We report on temperature-dependent pair distribution function measurements of Sr_{1-x}Na_{x}Fe_{2}As_{2}, an iron-based superconductor system that contains a magnetic phase with reentrant tetragonal symmetry, known as the magnetic C_{4} phase. Quantitative refinements indicate that the instantaneous local structure in the C_{4} phase comprises fluctuating orthorhombic regions with a length scale of ∼2  nm, despite the tetragonal symmetry of the average static structure. Additionally, local orthorhombic fluctuations exist on a similar length scale at temperatures well into the paramagnetic tetragonal phase.

Flux Crystal Growth of the RERuGe (RE = La, Ce, Nd, Gd, Tb) Series and Their Magnetic and Metamagnetic Transitions.

Previously synthesized only as powders, single crystals of the RERuGe (RE = La, Ce, Nd, Gd, Tb) series of compounds have now been obtained from molten In. These materials crystallize with the UCoSi-type structure in orthorhombic space group Ibam with lattice parameters a ≈ 10.00-9.

Hybridization Gap in the Semiconducting Compound SrIrInGe.

Large single crystals of SrIrInGe were synthesized using the In flux method. This compound is a hybridization gap semiconductor with an experimental optical band gap of E = 0.25(3) eV.

Mixed-Valent NaCu4Se3: A Two-Dimensional Metal.

The new ternary copper selenide NaCu4Se3 crystallizes in the RbCd4As3 structure type with the trigonal space group R3̅m and lattice constants a = 4.0316(4) Å and c = 31.438(8) Å.

Metallic Borides, La2Re3B7 and La3Re2B5, Featuring Extensive Boron-Boron Bonding.

La2Re3B7 and La3Re2B5 have been synthesized in single-crystalline form from a molten La/Ni eutectic at 1000 °C in the first example of the flux crystal growth of ternary rare-earth rhenium borides. Both compounds crystallize in their own orthorhombic structure types, with La2Re3B7 (space group Pcca) having lattice parameters a = 7.657(2) Å, b = 6.

Crystal Growth, Structures, and Properties of the Complex Borides, LaOs2Al2B and La2Os2AlB2.

Single crystals of two novel quaternary metal borides, LaOs2Al2B and La2Os2AlB2, have been grown from La/Ni eutectic fluxes. LaOs2Al2B crystallizes in tetragonal space group P4/mmm with the CeCr2Si2C-type structure, and lattice parameters a = 4.2075(6) Å and c = 5.

Hybridization Gap and Dresselhaus Spin Splitting in EuIr4In2Ge4.

EuIr4In2Ge4 is a new intermetallic semiconductor that adopts a non-centrosymmetric structure in the tetragonal I4̄2m space group with unit cell parameters a=6.9016(5) Å and c=8.7153(9) Å.

NaCu6Se4: a layered compound with mixed valency and metallic properties.

A new ternary compound NaCu6Se4 was synthesized from the reaction of Cu in a molten sodium polyselenide flux. The compound crystallizes in trigonal space group R3̅m with a = 4.0465(3) Å and c = 41.

Crystal growth and characterization of the narrow-band-gap semiconductors OsPn₂ (Pn = P, As, Sb).

Using metal fluxes, crystals of the binary osmium dipnictides OsPn2 (Pn = P, As, Sb) have been grown for the first time. Single-crystal X-ray diffraction confirms that these compounds crystallize in the marcasite structure type with orthorhombic space group Pnnm. The structure is a three-dimensional framework of corner- and edge-sharing OsPn6 octahedra, as well as [Pn2(4-)] anions.

Magnetically driven suppression of nematic order in an iron-based superconductor.

A theory of superconductivity in the iron-based materials requires an understanding of the phase diagram of the normal state. In these compounds, superconductivity emerges when stripe spin density wave (SDW) order is suppressed by doping, pressure or atomic disorder. This magnetic order is often pre-empted by nematic order, whose origin is yet to be resolved.

Exotic magnetism on the quasi-fcc lattices of the d3 double Perovskites La2NaB'O6 (B'=Ru, Os).

We find evidence for long-range and short-range (ζ=70 Å at 4 K) incommensurate magnetic order on the quasi-face-centered-cubic (fcc) lattices of the monoclinic double perovskites La2NaRuO6 and La2NaOsO6, respectively. Incommensurate magnetic order on the fcc lattice has not been predicted by mean field theory, but may arise via a delicate balance of inequivalent nearest neighbor and next nearest neighbor exchange interactions. In the Ru system with long-range order, inelastic neutron scattering also reveals a spin gap Δ ∼ 2.

Crystal growth of new hexahydroxometallates using a hydroflux.

A series of seven compounds, Sr2Mn(OH)6, Ba2Mn(OH)6, Sr2Co(OH)6, Ba2Co(OH)6, Sr2Ni(OH)6, Ba2Ni(OH)6, and Ba2Cu(OH)6, were synthesized using a low-melting hydroflux, a hybrid approach between aqueous hydrothermal and molten hydroxide flux techniques. Crystals of the hexahydroxometallates were obtained by dissolving appropriate amounts of alkaline-earth nitrates or hydroxides and transition-metal oxides, acetates, or chlorides in the hydroflux and reacting at 180-230 °C. The isostructural compounds all crystallize in the monoclinic space group P2(1/n).

Hydroflux crystal growth of platinum group metal hydroxides: Sr6NaPd2(OH)17, Li2Pt(OH)6, Na2Pt(OH)6, Sr2Pt(OH)8, and Ba2Pt(OH)8.

Crystals of five complex metal hydroxides containing platinum group metals were grown by a novel low-temperature hydroflux technique, a hybrid approach between the aqueous hydrothermal and the molten hydroxide flux techniques. Sr6NaPd2(OH)17 (1) crystallizes in orthorhombic space group Pbcn with lattice parameters a = 19.577(4) Å, b = 13.

Li3Al(MoO4)3, a lyonsite molybdate.

Trilithium aluminium trimolybdate(VI), Li(3)Al(MoO(4))(3), has been grown as single crystals from α-Al(2)O(3) and MoO(3) in an Li(2)MoO(4) flux at 998 K. This compound is an example of the well known lyonsite structure type, the general formula of which can be written as A(16)B(12)O(48). Because this structure can accomodate cationic mixing as well as cationic vacancies, a wide range of chemical compositions can adopt this structure type.

Unveiling structure-property relationships in Sr2Fe(1.5)Mo(0.5)O(6-δ), an electrode material for symmetric solid oxide fuel cells.

We characterize experimentally and theoretically the promising new solid oxide fuel cell electrode material Sr(2)Fe(1.5)Mo(0.5)O(6-δ) (SFMO).

Materials discovery by flux crystal growth: quaternary and higher order oxides.

This Review highlights the application of high-temperature solutions for exploratory crystal growth and materials discovery of novel complex oxides. It provides an overview of the method of flux crystal growth of complex oxides and can function as a "how to" guide for those interested in oxide crystal growth. The most commonly used fluxes are discussed in terms of their applicability for dissolving specific elements and the typical reaction conditions are compiled.

Ba8Hg3U3S18: a complex uranium(+4)/uranium(+5) sulfide.

The compound Ba(8)Hg(3)U(3)S(18) was obtained from the solid-state reaction at 1123 K of U, HgS, BaS, and S, with BaBr(2)/KBr or BaCl(2) as a flux. This material crystallizes in a new structure type in space group P6 of the hexagonal system with three formula units in a cell of dimensions a = 27.08(1) Å, c = 4.

Pentavalent and tetravalent uranium selenides, Tl3Cu4USe6 and Tl2Ag2USe4: syntheses, characterization, and structural comparison to other layered actinide chalcogenide compounds.

The compounds Tl(3)Cu(4)USe(6) and Tl(2)Ag(2)USe(4) were synthesized by the reaction of the elements in excess TlCl at 1123 K. Both compounds crystallize in new structure types, in space groups P2(1)/c and C2/m, respectively, of the monoclinic system. Each compound contains layers of USe(6) octahedra and MSe(4) (M = Cu, Ag) tetrahedra, separated by Tl(+) cations.

Dichalcogenide bonding in seven alkali-metal actinide chalcogenides of the KTh2Se6 structure type.

The solid-state compounds CsTh(2)Se(6), Rb(0.85)U(1.74)S(6), RbU(2)Se(6), TlU(2)Se(6), Cs(0.

Syntheses and characterization of some solid-state actinide (Th, U, Np) compounds.

In this Perspective we discuss a variety of methods that are broadly applicable to the syntheses of solid-state compounds. To illustrate the application of these methods we use solid-state actinide compounds, an area of chemistry that has been the focus of this laboratory for the last decade. We have synthesized single crystals, primarily of actinide chalcogenide compounds, by a variety of techniques.

La2U2Se9: an ordered lanthanide/actinide chalcogenide with a novel structure type.

The compound La(2)U(2)Se(9) was obtained in high yield from the stoichiometric reaction of the elements in an Sb(2)Se(3) flux at 1123 K. The compound, which crystallizes in a new structure type in space group Pmma of the orthorhombic system, has a three-dimensional structure with alternating U/Se and La/Se layers attached via three independent, infinite polyselenide chains. The U atom has a monocapped square antiprismatic coordination of Se atoms, whereas one La atom is bicapped square prismatic and the other La atom is trigonal prismatic.

BaLn2Se4 (Ln = Er, Tm and Yb).

The compounds BaLn(2)Se(4) (Ln = rare-earth metal = lanthanide = Er, Tm and Yb), namely barium di(erbium/thulium/ytterbium) tetraselenide, crystallize in the orthorhombic space group Pnma in the CaFe(2)O(4) structure type. In this structure type, all atoms possess m symmetry. The Ln atoms are octahedrally coordinated by six Se atoms.

Syntheses, crystal structures, and physical properties of La5Cu6O4S7 and La5Cu6.33O4S7.

Single crystal and bulk powder samples of the quaternary lanthanum copper oxysulfides La5Cu6.33O4S7 and La5Cu6O4S7 have been prepared by means of high-temperature sealed-tube reactions and spark plasma sintering, respectively. In the structure of La 5Cu6.