Forcing substitution of tantalum by copper in 1T-TaS: synthesis, structure and electronic properties of 1T-Cu Ta S.

We investigated the compound 1T-Cu Ta S with respect to its synthesis, homogeneity range, structure and electronic properties. The average structure of 1T-Cu Ta S resembles that of the high-temperature phase of the layered transition metal dichalcogenide 1T-TaS in which tantalum is partially substituted by copper. 1T-Cu Ta S readily decomposes at elevated temperatures and can only be prepared and stabilized by a sufficiently high amount of sulfur excess.

Penta-lanthanum zinc diplumbide, La5Zn1-x Pb2+x (x ≃ 0.6).

The title non-stoichiometric penta-lanthanum zinc diplumbide, La5Zn1-x Pb2+x (x ≃ 0.6), was prepared from the elements in an evacuated silica ampoule. It adopts the Nb5Sn2Si-type structure (space group I4/mcm, Pearson symbol tI32), a ternary ordered superstructure of the W5Si3 type.

Facile one-pot fabrication of hollow porous silica nanoparticles.

A method for the fabrication of hollow silica nanospheres, a facile one-pot hydrothermal route, is described. Heating of an aqueous solution of water glass and D-glucose to 180 °C for 24 h affords-as indicated by transmission electron microscopy-a nanospherical composite consisting of a silica shell sheathing a carbonaceous core. Subsequent removal of the carbonaceous interior through oxidation in air produces hollow silica structures.

Dissolution kinetics of nanocrystals.

A simple series of test-tube experiments is all it takes to quantify a largely neglected nano-effect responsible for a dramatic increase-by orders of magnitude-in the surface-area-normalized rate of dissolution of nanocrystals. Though the observed variation in this specific rate as a function of size is unprecedented, the effect may be rationalized in terms of the classic atomistic theory of crystal growth and dissolution.

Site preference and ordering induced by Au substitution in the γ-brass related complex Au-Cr-Zn phases.

The crystal chemistry of the ternary Au-Cr-Zn alloy was studied by means of synthesis, single crystal X-ray diffraction, and electron structure calculations. While the compound CrZn(∼17) represents the binary end-point of the homogeneity range, the inclusion of Au proves to be very site specific, and at the limiting composition Au10Cr4Zn89 the structure is completely ordered. The crystallographic site occupancy pattern calculated by the Local Density Approximation (LDA)-Density Functional Theory (DFT) parametrized extended Hückel (eH) Mulliken charge populations in Au10Cr4Zn89 agrees very well with the experimentally found site occupancy pattern.

Self-organization of multifunctional surfaces--the fingerprints of light on a complex system.

Nanocomposite patterns and nanotemplates are generated by a single-step bottom-up concept that introduces laser-induced periodic surface structures (LIPSS) as a tool for site-specific reaction control in multicomponent systems. Periodic intensity fluctuations of this photothermal stimulus inflict spatial-selective reorganizations, dewetting scenarios and phase segregations, thus creating regular patterns of anisotropic physicochemical properties that feature attractive optical, electrical, magnetic, and catalytic properties.

Multiplicative congruential generators, their lattice structure, its relation to lattice-sublattice transformations and applications in crystallography.

An analysis of certain types of multiplicative congruential generators--otherwise known for their application to the sequential generation of pseudo-random numbers--reveals their relation to the coordinate description of lattice points in two-dimensional primitive sublattices. Taking the index of the lattice-sublattice transformation as the modulus of the multiplicative congruential generator, there are special choices for its multiplier which induce a symmetry-preserving permutation of lattice-point coordinates. From an analysis of similar sublattices with hexagonal and square symmetry it is conjectured that the cycle structure of the permutation has its crystallographic counterpart in the description of crystallographic orbits.

Large, larger, largest--a family of cluster-based tantalum copper aluminides with giant unit cells. II. The cluster structure.

This is the second of two papers, where we discuss the cluster structures of a novel family of cluster-based intermetallic phases of unprecedented complexity: cF444-Al(63.6)Ta(36.4) (AT-19), a = 19.

Large, larger, largest--a family of cluster-based tantalum copper aluminides with giant unit cells. I. Structure solution and refinement.

This is the first of two parts, where we report the structure determination of a novel family of cluster-based intermetallic phases of unprecedented complexity: cF444-Al(63.6)Ta(36.4) (AT-19), a = 19.

The valence problem of Pd4Br4Te3.

Pd(4)Br(4)Te(3) was prepared from Pd, Te, and PdBr(2) at 700 K. Its structure was determined by single-crystal X-ray diffraction to be triclinic, P$\bar 1$, Pearson symbol aP22; a=842.5(2), b=845.

Synthesis, crystal structure and some physical properties of RuZn3.

The crystal structure, phase relations and some physical properties of the binary zinc-rich phase RuZn3 are reported. The title compound is accessible via high-temperature reaction from the elements in the appropriate substance amount ratio. Its crystal structure was determined from a Rietveld profile fit to an X-ray diffractogram of pristine RuZn3 and confirmed by single-crystal X-ray structure analysis.

Pd(0.213)Cd(0.787) and Pd(0.235)Cd(0.765) structures: their long c axis and composite crystals, chemical twinning, and atomic site preferences.

We present single-crystal studies of Pd(0.213)Cd(0.787) and Pd(0.

Ferrimagnetic nanogranular Co3O4 through solvothermal decomposition of colloidally dispersed monolayers of alpha-cobalt hydroxide.

Co3O4 nanoparticles of 35 nm with a cauliflower-like morphology were obtained when a monolayer colloidal dispersion of dodecyl sulfate intercalated alpha-cobalt hydroxide in butanol was subjected to solvothermal hydrolytic decomposition. The nanogranular particles exhibit weakly ferromagnetic properties in contrast with both bulk and dispersed nanoparticulate Co3O4.

Structure-composition relations for the partly disordered Hume-Rothery phase Ir7+7deltaZn97-11delta (0.31< or =delta< or =0.58).

The crystal structure, its variation within the homogeneity range and some physical properties of the new zinc-rich, partly disordered phase Ir7+7deltaZn97-11delta (0.31< or =delta< or =0.58) are reported.

Ta97Te60: a crystalline approximant of a tantalum telluride quasicrystal with twelvefold rotational symmetry.

The crystal structure of a rational approximant of an unprecedented dodecagonal quasicrystal is reported. The atomic arrangement of the tantalum-rich telluride Ta(97)Te(60) has been determined from 30 458 symmetrically independent X-ray intensities of a crystal twinned by metric merohedry: a=2767.2(2), b=2767.

Synthesis and Crystal Structure of Zr(2)Te. Distinctions in Bonding to Isotypic Sc(2)Te and the Relationship to the Structures of Congeneric Hf(2)Te and Zr(2)Se.

Zr(2)Te is accessible by high-temperature synthesis. The structure of the zirconium-rich telluride was determined by means of powder X-ray diffraction to be orthorhombic, Pnma (No. 62), Z = 12, Pearson symbol oP36, a = 1995.

A Dodecagonal Quasicrystalline Chalcogenide.

Diffractograms with twelvefold rotational symmetry (depicted on the right) were obtained from the first quasicrystalline chalcogenide Ta Te. This compound was prepared on a preparative scale by the reduction of TaTe with tantalum below 1870 K. This tantalum-rich telluride, which is the first stable dodecagonal phase, has enabled an in-depth investigation of this unusual state of ordering.