Photoluminescent chain-of-dimer anion in a novel hybrid halometallate (CHN){SbBr}: atypical behavior in one-dimensional anionic systems.

In pursuit of identifying less toxic hybrid compounds suitable for optoelectronic applications, we synthesized a novel homopiperazinium bromoantimonate(III), (CHN){SbBr}. It readily crystallized from an aqueous hydrobromic acid solution and was found to be stable both in air and upon heating up to 175 °C. The crystal structure of the new bromoantimonate(III) consisted of {SbBr} zigzag chains, which were composed of strongly trigonally distorted SbBr octahedral anions and CHN dications.

Crystal structure, Chemical Bonding, and Magnetism of α-FeGa: How Local Interactions Shape the Structure and Properties of Intermetallic Compounds.

α-FeGa was synthesized from the elements as a polycrystalline powder. Its crystal structure was redetermined by high-resolution powder X-ray diffraction, which showed a complex monoclinic structure of the FeGe type. The determined lattice parameters ( = 10.

MnGaS and MnAlSe van der Waals Chalcogenides: A Source of Atomically Thin Nanomaterials.

Layered chalcogenides containing 3d transition metals are promising for the development of two-dimensional nanomaterials with interesting magnetic properties. Both mechanical and solution-based exfoliation of atomically thin layers is possible due to the low-energy van der Waals bonds. In this paper, we present the synthesis and crystal structures of the MnGaS and MnAlSe layered chalcogenides.

Bulk ferromagnetism in cleavable van der Waals telluride NbFeTe.

A van der Waals telluride, NbFeTe, has been synthesized using chemical vapor transport reactions. The optimized synthetic conditions yield high-quality single crystals with a novel monoclinic crystal structure. Monoclinic NbFeTe demonstrates a (100) cleavage plane, bulk ferromagnetism below 87 K, and a metallic ground state-the necessary prerequisites for needed spintronics technologies.

Interplay of two magnetic sublattices in related compounds SmMnGaGe ( = 0.1-0.3, = 0.6-1.0) and SmMnGaGe ( = 3.0-3.5) with different ordering of empty and filled (Ga,Ge) octahedra.

Single crystals of two new intermetallic phases SmMnGaGe ( = 0.1-0.3, = 0.

Impact of Ge Doping on Structural and Magnetic Ordering in RMnGa and RMnGaGe (R = Tb, Dy; ≤ 0.25, ≈ 1.0-3.3).

Single crystals of RMnGa and their new quaternary derivatives RMnGaGe (R = Tb, Dy, ≤ 0.25, ≈ 1.0-3.

Itinerant ferromagnet ReMnGe ( = 0.9-1.5, = 0.42-0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure.

ReMnGe ( = 0.9-1.5, = 0.

Layered van der Waals Chalcogenides FeAlSe, MnAlS, and MnAlSe: Atomically Thin Triangular Arrangement of Transition-Metal Atoms.

Layered van der Waals (vdW) chalcogenides of 3d transition metals are a rich source of two-dimensional (2D) nanomaterials, in which atomically thin layers with the terminating chalcogen atoms exhibit promising functionality for novel spintronic devices. Here, we report on the synthesis, crystal growth, and magnetic properties of FeAlSe, MnAlS, and MnAlSe ternary chalcogenides. Crystal structures are probed by powder X-ray diffraction, Mössbauer spectroscopy, and high-resolution transmission electron microscopy.

Cleavable crystals, crystal structure, and magnetic properties of the NbFeTe layered van der Waals telluride.

Transition metal-based two-dimensional nanomaterials with competing magnetic states are at the cutting edge of spintronic and low-power memory devices. In this paper, we present a Fe-rich NbFeTe layered telluride ( ≈ 0.5), which shows an interplay of spin-glass and antiferromagnetic states below the Néel temperature of 179 K.

Controlled Reduction of Sn in the Complex Iodide CsSnI with Metallic Gallium.

Metal gallium as a low-melting solid was applied in a mixture with elemental iodine to substitute tin(IV) in a promising light-harvesting phase of CsSnI by a reactive sintering method. The reducing power of gallium was applied to influence the optoelectronic properties of the CsSnI phase via partial reduction of tin(IV) and, very likely, substitute partially Sn by Ga. The reduction of Sn to Sn in the CsSnI phase contributes to the switching from -type conductivity to n-type, thereby improving the total concentration and mobility of negative-charge carriers.

Synthesis, Crystal, and Electronic Structure of (HpipeH)[SbI](I), with I Molecules Linking SbX Dimers into a Polymeric Anion: A Strategy for Optimizing a Hybrid Compound's Band Gap.

In searching for a tool for optimizing the band gap of a hybrid compound capable of serving as a light-harvesting material in lead-free photovoltaics, we synthesized a new polyiodoantimonate (HpipeH)[SbI](I) and analyzed its crystal and electronic structure by application of X-ray crystal structure analysis, Raman and diffuse reflectance spectroscopies, and quantum chemical calculations. It was demonstrated that I molecules link SbI edge-sharing octahedra into zig-zag chains, whereas the organic cations link inorganic anionic chains into a 3D structure featuring a complex pattern of covalent bonds and non-covalent interactions. Overall, these features provide the background for forming the electronic structure with a narrow band gap of 1.

Effect of antifluorite layer on the magnetic order in Eu-based 1111 compounds, EuTAsF (T = Zn, Mn, and Fe).

The 1111 compounds with an alternating sequence of fluorite and antifluorite layers serve as structural hosts for the vast family of Fe-based superconductors. Here, we use neutron powder diffraction and density-functional-theory (DFT) band-structure calculations to study magnetic order of Eu in the [EuF] fluorite layers depending on the nature of the [TAs] antifluorite layer that can be non-magnetic semiconducting (T = Zn), magnetic semiconducting (T = Mn), or magnetic metallic (T = Fe). Antiferromagnetic transitions at ∼ 2.

Fe-Rich Ferromagnetic Cleavable Van der Waals Telluride FeAsTe.

Transition metal-based layered compounds with van der Waals gaps between the structural layers are a rich source of magnetic materials for spintronic applications. Bulk crystals can be cleaved, providing high-quality two-dimensional nanomaterials, which are promising for the manipulation of spins in spintronic devices and low power quantum logic interfaces. The layered van der Waals telluride FeAsTe can be synthesized by the high-temperature reaction of elements.

Ferromagnetic correlations in the layered van der Waals sulfide FeAlS.

Transition metal-based layered compounds with van der Waals gaps between the adjacent layers are a source of two-dimensional (2D) nanomaterials with nontrivial transport and magnetic properties. 2D ferromagnets, both metals and semiconductors, can be leveraged to produce spin-polarized current in spintronic devices with tailored functionalities. Here, we report on the synthesis, crystal growth, crystal and electronic structure, and magnetic properties of the Fe-based FeAlS layered sulfide.

Intermetallic Compound ReGaGe with Re- and Ge-Embedded Gallium Clusters: Synthesis, Crystal Structure, Chemical Bonding, and Physical Properties.

Transition metal-based endohedral cluster intermetallic compounds are interesting electron phases, which frequently exhibit superconductivity with a peculiar interplay between the critical temperature and valence electron count. We present a new Re-based endohedral gallium cluster compound, ReGaGe. Its unique crystal structure (4 space group, = 8.

Molecular and Supramolecular Structures of Triiodides and Polyiodobismuthates of Phenylenediammonium and Its N,N-dimethyl Derivative.

Despite remarkable progress in photoconversion efficiency, the toxicity of lead-based hybrid perovskites remains an important issue hindering their applications in consumer optoelectronic devices, such as solar cells, LED displays, and photodetectors. For that reason, lead-free metal halide complexes have attracted great attention as alternative optoelectronic materials. In this work, we demonstrate that reactions of two aromatic diamines with iodine in hydroiodic acid produced phenylenediammonium (PDA) and N,N-dimethyl-phenylenediammonium (DMPDA) triiodides, PDA(I)⋅2HO and DMPDA(I)I, respectively.

Endohedral cluster intermetallic superconductors: at the frontier between chemistry and physics.

When a transition metal combines with an excess of a p-metal, the latter forms endohedral clusters with the number of vertices up to 14. These clusters are the building units of endohedral cluster intermetallic compounds. Although discovered a few decades ago, they have gained renewed interest due to their peculiar crystal and electronic structures and frequently observed superconducting properties.

Intermetallic FeGe formation and decay of a core-shell structure during the oxygen evolution reaction.

Herein, we report on intermetallic iron germanide (Fe6Ge5) as a novel oxygen evolution reaction (OER) precatalyst with a Tafel slope of 32 mV dec-1 and an overpotential of 272 mV at 100 mA cm-2 in alkaline media. Furthermore, we uncover the in situ formation of a core-shell like structure that slowly collapses under OER conditions.

Indium Doping of Lead-Free Perovskite CsSnI.

Structure and properties of an inorganic perovskite CsSnI demonstrated its potential as a light-harvester or electron-hole transport material; however, its optoelectronic properties are poorer than those of lead-based perovskites. Here, we report the way of light tuning of absorption and transport properties of cesium iodostannate(IV) CsSnI via partial heterovalent substitution of tin for indium. Light absorption and optical bandgaps of materials have been investigated by UV-vis absorption and photoluminescent spectroscopies.

Electron-Precise Semiconducting ReGaGe: Extending the IrIn Structure Type to Group 7 of the Periodic Table.

Intermetallic compounds with semiconducting properties are rare, but they give rise to advanced materials for energy conversion and saving applications. Here, we present ReGaGe, a new electron-precise narrow-gap intermetallic semiconductor. The compound crystallizes in the IrIn structure type (space group 4/, = 6.

Assembling Polyiodides and Iodobismuthates Using a Template Effect of a Cyclic Diammonium Cation and Formation of a Low-Gap Hybrid Iodobismuthate with High Thermal Stability.

Exploiting a template effect of 1,4-diazacycloheptane (also known as homopiperazine, Hpipe), four new hybrid iodides, (HpipeH)BiI·2HO, (HpipeH)I(I), (HpipeH)I·HO, and (HpipeH)(HO)I, were prepared and their crystal structures were solved using single crystal X-ray diffraction data. All four solid-state crystal structures feature the HpipeH cation alternating with BiI, I, or I anions and solvent water or HO cation. HpipeH assembles anionic and neutral building blocks into polymer structures by forming four strong (N)H···I and (N)H···O hydrogen bonds per cation, with the H···I distances ranging from 2.

Synthesis, electronic structure and physical properties of two new layered compounds, EuFAgSe and EuFAgTe, featuring the active redox pair Eu/Ag.

Systematic studies of the ZrCuSiAs (also LaOAgS or 1111) structure type resulted in the synthesis of two new fluoride chalcogenides, EuFAgSe and EuFAg1-δTe, whereas their sulfide analog, EuFAgS, could not be obtained. Both new compounds are tetragonal, P4/nmm, with cell parameters a = 4.1542(1) Å, c = 9.

Endohedral Cluster Superconductors in the Mo-Ga-Sn System Explored by the Joint Flux Technique.

Endohedral Ga cluster compounds feature nontrivial superconducting states including the two-gap superconductivity similar in nature to MgB. We use the joint flux synthetic technique to introduce Sn into the Ga matrix and tune the valence electron count in the two new endohedral cluster superconductors MoGaSn and MoGaSn with critical temperatures of = 8.7 and 5.

Synthesis, crystal and electronic structures of Pt-rich phosphides EuPtP and EuPtP.

Two new ternary Pt-rich phosphides, EuPt6P2 and EuPt3P, have been prepared via a two-step solid state reaction. Their crystal structures have been determined from powder XRD data. EuPt6P2 is isostructural to SrPt6P2 (cubic, Pa3[combining macron], a = 8.

Single-gap superconductivity in MoGa.

In this paper, the potential existence of two-gap superconductivity in MoGa is addressed in detail by means of thermodynamic and spectroscopic measurements. A combination of highly sensitive bulk and surface probes, specifically ac-calorimetry and scanning tunneling spectroscopy (STS), are utilized on the same piece of crystal and reveal the presence of only one intrinsic gap in the system featuring strong electron-phonon coupling. Minute traces of additional superconducting phases detected by STS and also in the heat capacity measured in high magnetic fields on a high-quality and seemingly single-phase crystal might mimic the multigap superconductivity of MoGa suggested recently in several studies.