Are Selenides the Same as Sulfides? Structure, Spectroscopy, and Properties of Narrow-Gap Rare-Earth Semiconductors Sn(SSe) ( = La, Ce; = 0-0.8).

The ternary rare-earth sulfides SnS ( = La-Nd) and the partial solid solutions Sn(SSe) ( = La, Ce; = 0-0.8) were prepared in the form of polycrystalline samples by reaction of the elements at 900 °C and as single crystals in the presence of KBr flux. They adopt the LaSnS-type structure (orthorhombic, space group , = 2) consisting of chains of edge-sharing Sn octahedra separated by atoms.

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning.

Laves phases form the most abundant group of intermetallic compounds, consisting of combinations of larger electropositive metals with smaller metals . Many practical applications of Laves phases depend on the ability to tune their physical properties through appropriate substitution of either the or component. Although simple geometrical and electronic factors have long been thought to control the formation of Laves phases, no single factor alone can make predictions accurately.

Structure and Optical Properties of LiAgGaSe and LiAgInSe.

Complete substitution of Li atoms for Ag atoms in AgGaSe and AgInSe was achieved, resulting in the solid solutions LiAgGaSe and LiAgInSe. The detailed crystal structures were determined by single-crystal X-ray diffraction and solid-state Li nuclear magnetic resonance spectroscopy, which confirm that Li atoms occupy unique sites and disorder only with Ag atoms. The tetragonal CuFeS-type structure (space group 4̅2) was retained within the entirety of the Ga-containing solid solution LiAgGaSe, which is noteworthy because the end-member LiGaSe normally adopts the orthorhombic β-NaFeO-type structure (space group 2).

Effect of aliovalent bismuth substitution on structure and optical properties of CsSnBr.

Aliovalent substitution of the B component in ABX metal halides has often been proposed to modify the band gap and thus the photovoltaic properties, but details about the resulting structure have remained largely unknown. Here, we examine these effects in Bi-substituted CsSnBr. Powder X-ray diffraction (XRD) and solid-state Sn, Cs and Bi nuclear magnetic resonance (NMR) spectroscopy were carried out to infer how Bi substitution changes the structure of these compounds.

Anisotropic Near-Zero Thermal Expansion in REAg Ga ( RE = La-Nd, Sm, Eu, and Yb) Induced by Structural Reorganization.

In this work, we have discovered the anisotropic near-zero thermal expansion (NZTE) behavior in a family of compounds REAg Ga ( RE = La-Nd, Sm, Eu, and Yb). The compounds adopt the CeAlGa structure type and were obtained as single crystals in high yield by metal flux growth technique using gallium as active flux. Temperature-dependent single crystal X-ray diffraction suggests that all the compounds exhibit near zero thermal expansion along c direction in the temperature range of 100-450 K.

Crystal Engineering in Supramolecular Polyoxometalate Hybrids through pH Controlled in Situ Ligand Hydrolysis.

A family of five different three-dimensional polyoxometalate (POM) based supramolecular hybrids were synthesized by a hydrothermal route under different pH using a hydrolyzable naphthalene diimide ligand. The mechanism of crystallographic phase variation of the POM-amino pyridine hybrids under different pH was studied through controlled experiments where the final hydrolyzed products were analyzed through NMR and single crystal X-ray diffraction. Different pH conditions led to variation in the extent of protonation and hydrolyzation of the ligand, yielding different phases.

Facile Aqueous-Phase Synthesis of the PtAu/BiO Hybrid Catalyst for Efficient Electro-Oxidation of Ethanol.

In this work, we present a facile aqueous-phase synthesis of a hybrid catalyst consisting of PtAu alloy supported on BiO microspheres. Multistep reduction of HAuCl and KPtCl salts on BiO and subsequent annealing lead to the formation of this hybrid catalyst. To the best of our knowledge, this is the first report of using BiO as a catalyst support in fuel cell applications.