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By applying the alloy design concept that stable intermetallic phases between two immiscible elements can be formed by adding a third element that forms stable compounds with both elements, we have synthesized the first known stable intermetallic compound of Cu, Gd, and Ca, where copper acts as the mediating element between the immiscible Gd and Ca. A compound with the composition Cu84Gd9Ca7 (equivalent to Cu5Gd0.54Ca0.42) was synthesized by the Czochralski technique in the form of a large single crystal of high structural perfection, and the structural model was determined by x-ray diffraction (XRD). The compound crystallizes in the hexagonal system, space group P6/mmm, and the crystal structure is isotypic to the Cu5.44Tb0.78. The unit cell contains inherent disorder due to partial occupation of the Cu3 site and the substitutional disorder at the Gd/Ca mixed site located at the vertices of the hexagonal unit cell, where Gd and Ca randomly substitute each other. The random substitution of magnetic Gd by nonmagnetic Ca atoms makes the magnetic Gd lattice disordered, which leads to interesting magnetic ordering at low temperatures that occurs below TC=24K in zero and low external magnetic fields. By performing a large set of complementary experiments along two perpendicular crystallographic directions (the [001] hexagonal-axis direction and the [100] hexagonal-plane direction), we show that the zero-field collective magnetic state can be described as a random-anisotropy ferromagnetic state, where random magnetic anisotropies originate from the magnetic dipole interactions between the Gd moments in the magnetically disordered lattice. The random-anisotropy ferromagnetic state in the Cu84Gd9Ca7 is characterized by randomness and frustration of magnetic interactions, which are the two ingredients that allow classifying this state into the generic class of spin glasses. Our paper opens the possibility to search for new ternary intermetallic phases in the Cu-Gd-Ca phase diagram, including structurally complex phases and quasicrystals. [ABSTRACT FROM AUTHOR]

In the course of systematic studies of intermetallic compounds Ga 3 TM (TM─transition metal), the compound Ga 3 Rh is synthesized by direct reaction of the elements at 700 °C. The material obtained is characterized as a high-temperature modification of Ga 3 Rh. Powder and single-crystal X-ray diffraction analyses reveal tetragonal symmetry (space group P 4 2 / mnm , No. 146) with a = 6.4808(2) Å and c = 6.5267(2) Å. Large values and strong anisotropy of the atomic displacement parameters of Ga atoms indicate essential disorder in the crystal structure. A split-position technique is applied to describe the real crystal structure of ht -Ga 3 Rh. Bonding analysis in ht -Ga 3 Rh performed on ordered models with the space groups P 1̅, P 4 2 nm , and P 4 2 2 1 2 shows, besides the omnipresent heteroatomic Ga-Rh bonds in the rhombic prisms ∞ 3 [Ga 8/2 Rh 2 Rh shows temperature-dependent electrical resistivity of a "bad metal". The very low lattice thermal conductivity of less than 0.5 W m ht -Ga 3 Rh shows temperature-dependent electrical resistivity of a "bad metal". The very low lattice thermal conductivity of less than 0.5 W m -1 K -1 at 300 K, being lower than those for most other Ga 3 TM compounds, correlates with the enhanced bonding complexity.

The Zintl phase CaSi 2 is a layered compound with stacking variants known as 1P, 3R, and 6R. We extend the series by the 21R polytype formed by rapid cooling of the melt. The crystal structure of 21R-CaSi 2 (space group R 3̅ m ) was derived from HRTEM images, and the atomic positions were optimized by using the FPLO code ( a = 3.868 Å, c = 107.276 Å). We explore polytype transformations by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron backscattering diffraction (EBSD), and thermal analysis. While 6R-CaSi 2 is thermodynamically stable at ambient conditions, nanosized impurities of silicon stabilize 3R-CaSi 2 as a bulk phase.

LiCa 8 [Cr IV N 3 ] 2 N 2 F ( Pnnm (#58), a = 17.5230(13) Å, b = 7.3379(5) Å, c = 4.9433(4) Å) is an example of a multinary nitridochromate fluoride, that provides additional information on almost elusive tetravalent nitridochromates. Shorter Cr-N bond lengths compared to those in the previously reported nitridochromates(III), as well as diamagnetic behavior and vibrational spectroscopy data suggest Cr(IV), which is in good agreement with the charge balance and crystal structure refinement. According to band structure calculations, LiCa 8 [Cr IV N 3 ] 2 N 2 F is a semiconductor with a band gap of 1.1 eV. The compound features trigonal planar [CrN 3 ] 5 - units of C s symmetry, and lithium, calcium, nitrogen and fluorine atoms arranged in a fragment of the rock salt type structure.

The unusually high oxidation state + IV of cobalt is stabilized by ligands based on [B 11 H 11 ] 4- in dark blue colored Cs 4 [Co(B 11 H 10.11 (OH) 0.75 ) 2 ]·4.56H 2 O, K 4 [Co(B 11 H 9.19 (OH) 1.81 ) 2 ]·2H 2 O, Cs 8 [Co{(B 11 H 6 ) 2 (O)(O 2 BOH) 4 }] 2 ·4H 2 O and K 4 [Co{(B 11 H 6 ) 2 (O 2 BOH) 5 }]·7H 2 O. These compounds were obtained by reacting Co 2+ salts with [B 11 H 14 ] - under alkaline conditions. In the absence of oxygen, Co(+III) compounds such as the light brownish K 4 [Co(B 11 H 11 )(CN) 3 ]·KCl·2.5H 2 O are formed. The title compounds were characterized by X-ray crystallography. Cs 8 [Co{(B 11 H 6 ) 2 (O)(O 2 BOH) 4 }] 2 ·4H 2 O and K 4 [Co(B 11 H 11 )(CN) 3 ]·KCl·2.5H 2 O were also characterized using IR-, UV-vis and cyclovoltammetry. Magnetic measurements of Cs 4 [Co(B 11 H 10.11 (OH) 0.75 ) 2 ]·4.56H 2 O and ESR measurements of Cs 8 [Co{(B 11 H 6 ) 2 (O)(O 2 BOH) 4 }] 2 ·4H 2 O show that in these Co(+IV) low-spin d 5 complexes the unpaired electron is on the d x 2- y 2 , d xy ( E 2g ) orbitals.

Samples of the pseudo-binary system Na 2- x Li x Ga 7 ( x ≤ 1) were synthesized from the elements at 300 °C in sealed Ta ampoules or by the reaction of Na 2 Ga 7 with LiCl. The peritectic formation temperature decreases with increasing Li content from 501(2) °C ( x = 0) to 489(2) °C ( x = 1). The boundary compositions Na 2 Ga 7 and Na 1 Li 1 Ga 7 crystallize with different structure types related by a group-subgroup relation. While the Na-rich compositions ( x ≤ 0.5) represent a substitutional solid solution (space group Pnma ), the Li-rich compositions feature an unconventional replacement mechanism in which Li atoms occupying interstitial positions induce vancancies at the Na positions (space group Cmce ). The crystal structure of Na 1 Li 1 Ga 7 ( a = 8.562(1) Å, b = 14.822(2) Å, c = 11.454(2) Å; Z = 8) was determined from X-ray single-crystal diffraction data, and reveals an anionic framework comprising 12-bonded Ga 12 icosahedra and 4-bonded Ga atoms, with alkali-metal atoms occupying channels and cavities. The arrangement of cations makes NaLiGa 7 a new structure type within the MgB 12 Si 2 structure family. Band structure calculations for the composition NaLiGa 7 predict semiconducting behavior consistent with the balance [Na + ] 2 [Li + ] 2 [(Ga 12 ) 2- ][Ga - ] 2 , considering closo Wade clusters [(12b)Ga 12 ] 2- and Zintl anions [(4b)Ga] - . Susceptibility measurements indicate temperature-independent diamagnetic behavior.

During the investigation of the binary system Be-Ru two new phases - Be 7 Ru 4 and Be 12 Ru 7 - with similar compositions (63.6 at. % Be and 63.2 at. % Be, respectively), are discovered. They both represent new structural prototypes. The phases are located between Be 2 Ru (Fe 2 P-type structure) and Be 3 Ru 2 (U 3 Si 2 -type structure) in the phase diagram. This explains why their crystal structures, solved and refined from single crystal X-ray diffraction data, are described as 2D intergrowth of Fe 2 P and U 3 Si 2 motives. The calculated electronic density of stats (DOS) reveals pronounced minima in the vicinity of the Fermi level for both compounds. Position-space analysis of chemical bonding exhibits the formation of three- and four-atomic polar bonds, involving both, Ru and Be, atoms, and a strong charge transfer from Be to the more electronegative Ru., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

The quaternary nitridochromate(IV) LiSr 2 [CrN 3 ] crystallizes in a new structure type with the non-centrosymmetric space group P 2 1 (no. 4) with a = 5.5685(7) Å, b = 5.3828(8) Å, c = 7.5381(1) Å, and β = 92.291(8)°. Predominant structural features of the compound are slightly nonplanar trigonal units [CrN 3 ] 5- , which are connected by three-fold coordinated lithium to form slabs in the (001) plane. Shorter Cr-N bond lengths in comparison with reported nitridochromates(III), as well as diamagnetic behavior and vibrational spectroscopy data indicate Cr(IV), which is in a good agreement with the charge balance. According to electronic structure calculations, the compound is a semiconductor with a band gap of 1.19 eV.

Clathrate phases with crystal structures exhibiting complex disorder have been the subject of many prior studies. Here we report syntheses, crystal and electronic structure, and chemical bonding analysis of a Li-substituted Ge-based clathrate phase with the refined chemical formula Ba 8 Li 5.0(1) Ge 41.0 , which is a rare example of ternary clathrate-I where alkali metal atoms substitute framework Ge atoms. Two different synthesis methods to grow single crystals of the new clathrate phase are presented, in addition to the classical approach towards polycrystalline materials by combining pure elements in desired stoichiometric ratios. Structure elucidations for samples from different batches were carried out by single-crystal and powder X-ray diffraction methods. The ternary Ba 8 Li 5.0(1) Ge 41.0 phase crystallizes in the cubic type-I clathrate structure (space group Pm 3̄ n no. 223, a ≈ 10.80 Å), with the unit cell being substantially larger compared to the binary phase Ba 8 Ge 43 (Ba 8 □ 3 Ge 43 , a ≈ 10.63 Å). The expansion of the unit cell is the result of the Li atoms filling vacancies and substituting atoms in the Ge framework, with Li and Ge co-occupying one crystallographic (6 c ) site. As such, the Li atoms are situated in four-fold coordination environment surrounded by equidistant Ge atoms. Analysis of chemical bonding applying the electron density/electron localizability approach reveals ionic interaction of barium with the Li-Ge framework, while the lithium-germanium bonds are strongly polar covalent.

The structural features of the hexagonal layered crystal structure of Be 2 Ru (a=5.7508(3) Å, c=3.0044(2) Å, space group P 6 ‾ ${\bar{6}}$ 2m) were investigated by single crystal X-ray diffraction and transmission electron microscopy (TEM). The residual electron density and high-resolution TEM images show that the real structure can be described as an intergrowth of the main hexagonal matrix of the Fe 2 P type with minor orthorhombic inclusions of its stacking variants. Such atomic arrangement is stabilized by the charge transfer from Be to Ru and by a system of polar three- and four-atomic bonds involving both components. The calculated electronic density of states (DOS) of Be 2 Ru revealed, contrarily to typical intermetallic compounds, a pseudo gap (dip) in the vicinity of the Fermi level. The temperature dependence of the electrical resistivity of Be 2 Ru shows metal behaviour in agreement with the non-zero DOS at the Fermi level., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Na 2 Ga 7 crystallizes with the orthorhombic space group Pnma (no. 62; a = 14.8580(6) Å, b = 8.6766(6) Å, and c = 11.6105(5) Å; Z = 8) and constitutes a filled variant of the Li 2 B 12 Si 2 structure type. The crystal structure consists of a network of icosahedral Ga 12 units with 12 exohedral bonds and four-bonded Ga atoms in which the Na atoms occupy the channels and cavities. The atomic arrangement is consistent with the Zintl [(4b)Ga] - and Wade [(12b)Ga 12 ] 2- electron counting approach. The compound forms peritectically from Na 7 Ga 13 and the melt at 501 °C and does not show a homogeneity range. The band structure calculations predict semiconducting behavior consistent with the electron balance [Na + ] 4 [(Ga 12 ) 2- ][Ga - ] 2 . Magnetic susceptibility measurements show that Na 2 Ga 7 is diamagnetic.

The compound Ge 32 Co 9-x (x=0.54(6), a=10.9861(3) Å, space group Im 3 ‾ $\bar 3$ m) prepared under high pressure and at high temperature is metastable under ambient conditions. It crystallizes in a new structure type, Pearson symbol cI82-1.08. The crystal structure represents a slightly distorted cubic primitive arrangement of germanium atoms with part of the Ge cubes filled by cobalt. Analysis of the chemical bonding by real-space methods revealed three-core cluster units Ge 16 Co 3 and seemingly empty regions comprising either covalent inter-polyhedral Ge-Ge bonds or lone-pairs located at the germanium atoms. The electrical conductivity is metal-like., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Amalgams have played an important role in fundamental and applied solid-state chemistry and physics because of the diversity of crystallographic features and properties that they have to offer. Moreover, their peculiar chemical properties can sometimes give rise to unconventional superconducting or magnetic ground states. In the current work, we present an in-depth analysis of single crystals of YHg 3 and LuHg 3 (Mg 3 Cd structure type, space group P 6 3 / mmc ). Both compounds show superconductivity below T c = 1 ± 0.1 K (YHg 3 ) and T c = 1.2 ± 0.1 K (LuHg 3 ). Given the high air-sensitivity and toxicity of these compounds, this study was only possible using a number of dedicated experimental techniques., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

In the phase diagram U-Cd, only one compound has been identified so far─UCd 11 (space group Pm 3̅ m ). Since the discovery of this material, the physical properties of UCd 11 have attracted a considerable amount of attention. In particular, its complex magnetic phase diagram─as a result of tuning with magnetic field or pressure─is not well-understood. From a chemical perspective, a range of lattice parameter values have been reported, suggesting a possibility of a considerable homogeneity range, i.e. , UCd 11-x . In this work, we perform a simultaneous study of crystallographic features coupled with measurements of physical properties. This work sheds light on the delicate relationship between the intrinsic crystal chemistry and magnetic properties of UCd 11 .

The influence of structural disorder on superconductivity is not yet fully understood. A concurrent examination of crystallographic and physical properties of LaHg 6.4 reveals that this material enters a superconducting state below T c = 2.4 K while showing crystallographic disorder in one dimension. Lanthanum mercuride, which crystallizes in a new structure type (space group Cmcm , a = 9.779(2) Å, b = 28.891(4) Å, c = 5.0012(8) Å, Z = 8), has remained out of reach for nearly 50 years. In this crystal structure, strong disorder is present in the channels that propagate along the [001] direction. By implementing a combination of cutting-edge synthesis and characterization techniques, we were able to circumvent the complexity associated with the low formation temperature and chemical reactivity of this substance and study the superconductivity of LaHg 6.4 in detail.

In the absence of stand-alone one-to-one replacements for existing animal tests, efforts were made to integrate data from in silico , in chemico and in vitro methods to ensure sufficient mechanistic coverage of the skin sensitisation Adverse Outcome Pathway (AOP) and generate predictions suitable for hazard identification and potency sub-categorisation. A number of defined approaches (DAs), using fixed data interpretation procedures (DIP) to integrate data from multiple non-animal information sources, were proposed and documented using a standard reporting template developed by the Organisation for Economic Co-operation and Development (OECD). Subsequent international activities focused on the extensive characterisation of three of these DAs with respect to the reference in vivo data, applicability domains, limitations, predictive performances and characterisations of the level of confidence associated with the predictions. The ultimate product of this project was an OECD Guideline that provides information equivalent to that provided by the animal studies and that can be used to satisfy countries' regulatory data requirements for skin sensitisation. This Defined Approach Guideline was the first of its kind for the OECD, and provides an important precedent for regulatory adoption of human biology-relevant new approach methodologies with performances equivalent to, or better than, traditional animal tests. This mini review summarizes the principal features of the defined approaches described in OECD guideline 497., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Casati, Asturiol, Browne, Kleinstreuer, Régimbald-Krnel and Therriault.)

The new phase Be 3 Ru crystallizes with TiCu 3 -type structure (space group Pmmn (59), a=3.7062(1) Å, b=4.5353(1) Å, c=4.4170(1) Å), a coloring variant of the hexagonal closest packing (hcp) of spheres. The electronic structure revealed that Be 3 Ru has a pseudo-gap close to the Fermi level. A strong charge transfer from Be to Ru was observed from the analysis of electron density within the Quantum Theory of Atoms in Molecules (QTAIM) framework and polar three- and four-atomic Be-Ru bonds were observed from the ELI-D (electron localizability indicator) analysis. This situation is very similar to the recently investigated Be 5 Pt and Be 21 Pt 5 compounds. The unusual crystal chemical feature of Be 3 Ru is that different charged species belong to the same closest packing, contrary to typical inorganic compounds, where the cationic components are located in the voids of the closest packing formed by anions. Be 3 Ru is a diamagnet displaying metallic electrical resistivity., (© 2022 The Authors. Published by Wiley-VCH GmbH.)

High-entropy alloys (HEAs) are characterized by a simultaneous presence of a crystal lattice and an amorphous-type chemical (substitutional) disorder. In order to unravel the effect of crystal-glass duality on the electronic transport properties of HEAs, we performed a comparative study of the electronic transport coefficients of a 6-component alloy Al 0.5 TiZrPdCuNi that can be prepared either as a HEA or as a metallic glass (MG) at the same chemical composition. The HEA and the MG states of the Al 0.5 TiZrPdCuNi alloy both show large, negative-temperature-coefficient resistivity, positive thermopower, positive Hall coefficient and small thermal conductivity. The transport coefficients were reproduced analytically by the spectral conductivity model, using the Kubo-Greenwood formalism. For both modifications of the material (HEA and MG), contribution of phonons to the transport coefficients was found small, so that their temperature dependence originates predominantly from the temperature dependence of the Fermi-Dirac function and the variation of the spectral conductivity and the related electronic density of states with energy within the Fermi-level region. The very similar electronic transport coefficients of the HEA and the MG states point towards essential role of the immense chemical disorder., (© 2022. The Author(s).)

In this study, we investigate the scandium-containing Sc-Hf-Nb-Ta-Ti-Zr system of refractory high-entropy alloys (HEAs). Using the arc-melting method, we synthesized nine equimolar alloys (five 4-, three 5- and one 6-component), with all of them containing Sc. The alloys were characterized by XRD, electron microscopy and EDS, while superconductivity was investigated via electrical resistivity, specific heat and the Meissner effect. The results were compared to the parent Hf-Nb-Ta-Ti-Zr refractory HEAs, forming a single-phase body-centered cubic (bcc) structure and quite homogeneous microstructure. The addition of Sc produces a two-phase structure in the Sc-Hf-Nb-Ta-Ti-Zr alloys, with one phase being bcc and the other hexagonal close-packed (hcp). The hcp phase absorbs practically all Sc, whereas the Sc-poor bcc phase is identical to the bcc phase in the Hf-Nb-Ta-Ti-Zr parent system. Upon the Sc addition, the microstructure becomes very inhomogeneous. Large bcc dendrites (10-100 µm) are homogeneous in the central parts, but become a fine dispersion of sub-micron precipitates of the bcc and hcp phases close to the edges. The interdendritic regions are also a fine dispersion of the two phases. Superconductivity of the Sc-Hf-Nb-Ta-Ti-Zr alloys originates from the bcc phase fraction, which demonstrates identical superconducting parameters as the bcc Hf-Nb-Ta-Ti-Zr parent alloys, while the Sc-containing hcp phase fraction is non-superconducting.

The compound IrGa 3 was synthesized by direct reaction of the elements. It is formed as a high-temperature phase in the Ir-Ga system. Single-crystal X-ray diffraction analysis confirms the tetragonal symmetry (space group P 4 2 /mnm , No. 136) with a = 6.4623(1) Å and c = 6.5688(2) Å and reveals strong disorder in the crystal structure, reflected in the huge values and anisotropy of the atomic displacement parameters. A model for the real crystal structure of ht -IrGa 3 is derived by the split-position approach from the single-crystal X-ray diffraction data and confirmed by an atomic-resolution transmission electron microscopy study. Temperature-dependent electrical resistivity measurements evidence semiconductor behavior with a band gap of 30 meV. A thermoelectric characterization was performed for ht -IrGa 3 and for the solid solution IrGa 3- x Zn x ., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

In an attempt to incorporate tin (Sn) into high-entropy alloys composed of refractory metals Hf, Nb, Ti and Zr with the addition of 3 d transition metals Cu, Fe, and Ni, we synthesized a series of alloys in the system HfTiZrSn M ( M = Cu, Fe, Nb, Ni). The alloys were characterized crystallographically, microstructurally, and compositionally, and their physical properties were determined, with the emphasis on superconductivity. All Sn-containing alloys are multi-phase mixtures of intermetallic compounds (in most cases four). A common feature of the alloys is a microstructure of large crystalline grains of a hexagonal (Hf, Ti, Zr) 5 Sn 3 partially ordered phase embedded in a matrix that also contains many small inclusions. In the HfTiZrSnCu alloy, some Cu is also incorporated into the grains. Based on the electrical resistivity, specific heat, and magnetization measurements, a superconducting (SC) state was observed in the HfTiZr, HfTiZrSn, HfTiZrSnNi, and HfTiZrSnNb alloys. The HfTiZrSnFe alloy shows a partial SC transition, whereas the HfTiZrSnCu alloy is non-superconducting. All SC alloys are type II superconductors and belong to the Anderson class of "dirty" superconductors.

In a search for unconventional heavy-Fermion compounds with the localized 4f moments distributed quasiperiodically instead of a conventional distribution on a regular, translationally periodic lattice, we have successfully synthesized a stable Ce 3 Au 13 Ge 4 Tsai-type 1/1 quasicrystalline approximant of the off-stoichiometric composition Ce 3+ x Au 13+ y Ge 4+ z ( x = 0.17, y = 0.49, z = 1.08) and determined its structural model. The structure is body-centered-cubic (bcc), with space group Im 3̅, unit cell parameter a = 14.874(3) Å, and Pearson symbol cI 174, and can be described as a bcc packing of partially interpenetrating multishell rhombic triacontahedral clusters. The cerium sublattice, corresponding to the magnetic sublattice, consists of a bcc packing of Ce icosahedra with an additional Ce atom in a partially occupied site (occupation 0.7) at the center of each icosahedron. The measurements of its magnetic properties and the specific heat have demonstrated that it is a regular intermetallic compound with no resemblance to heavy-Fermion systems. The partially occupied Ce2 site in the center of each Ce1 icosahedron, the mixed-occupied Au/Ge ligand sites between the Ce2 and Ce1 atoms, and the random compositional fluctuations due to nonstoichiometry of the investigated Ce 3+ x Au 13+ y Ge 4+ z alloy introduce randomness into the Ce magnetic sublattice, which causes a distribution of the indirect-exchange antiferromagnetic interactions between the spins. Together with the geometric frustration of the triangularly distributed Ce moments, this leads to a spin-glass phase below the spin freezing temperature T f ≈ 0.28 K.

Skin sensitization test data are required or considered by chemical regulation authorities around the world. These data are used to develop product hazard labeling for the protection of consumers or workers and to assess risks from exposure to skin-sensitizing chemicals. To identify opportunities for regulatory uses of non-animal replacements for skin sensitization tests, the needs and uses for skin sensitization test data must first be clarified. Thus, we reviewed skin sensitization testing requirements for seven countries or regions that are represented in the International Cooperation on Alternative Test Methods (ICATM). We noted the type of skin sensitization data required for each chemical sector and whether these data were used in a hazard classification, potency classification, or risk assessment context; the preferred tests; and whether alternative non-animal tests were acceptable. An understanding of national and regional regulatory requirements for skin sensitization testing will inform the development of ICATM's international strategy for the acceptance and implementation of non-animal alternatives to assess the health hazards and risks associated with potential skin sensitizers., (Copyright © 2018 Elsevier Inc. All rights reserved.)