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The layered material α-RuCl3 is a promising candidate to realize the Kitaev quantum spin liquid (QSL) state. However, at ambient pressure, deviations from the perfect Kitaev geometry prevent the existence of the QSL state at low temperatures. Here we present the discovery of a pressure-induced high-symmetry phase in α-RuCl3, which creates close to ideal conditions for the emergence of a QSL. Employing a novel approach based on Bragg and diffuse scattering of synchrotron radiation, we reveal a pressure-induced reorganization of the RuCl3-layers. Most importantly, this reorganization affects the structure of the layers themselves, which acquire a high trigonal symmetry. For this trigonal phase the largest ratio between the Kitaev (K) and the Heisenberg exchange (J) ever encountered is found: K/J = 124. Additionally, we demonstrate that this phase can also be stabilized by a slight biaxial pressure. This not only resolves the conflicting reports of low-temperature structures in the literature, but also facilitates the investigation of the high-symmetry phase and its potential QSL using a range of experimental techniques. The layered material α-RuCl3 is a promising candidate for the Kitaev quantum spin liquid, but its low-temperature structure is debated. Here, using a new structural characterization approach, the authors report a pressure-induced high-symmetry phase in α-RuCl3, which might be close to the ideal Kitaev geometry. [ABSTRACT FROM AUTHOR]

Synthesizing intermetallic phases containing noble metals often poses a challenge as the melting points of noble metals often exceed the boiling point of bismuth (1560 °C). Reactions in the solid state generally circumvent this issue but are extremely time consuming. A convenient method to overcome these obstacles is the co-reduction of metal salts in polyols, which can be performed within hours at moderate temperatures and even allows access to metastable phases. However, little attention has been paid to the formation mechanisms of intermetallic particles in polyol reductions. Identifying crucial reaction parameters and finding patterns are key factors to enable targeted syntheses and product design. Here, we chose metastable γ-BiPd as an example to investigate the formation mechanism from mixtures of metal salts in ethylene glycol and to determine critical factors for phase formation. The reaction was also monitored by in situ X-ray diffraction using synchrotron radiation. Products, intermediates and solutions were characterized by (in situ) X-ray diffraction, electron microscopy, and UV-Vis spectroscopy. In the first step of the reaction, elemental palladium precipitates. Increasing temperature induces the reduction of bismuth cations and the subsequent rapid incorporation of bismuth into the palladium cores, yielding the γ-BiPd phase., (© 2023 The Authors. ChemistryOpen published by Wiley-VCH GmbH.)

High-efficient and fast adsorption of uranium is important to reduce the hazards caused by the uranium contamination of water environment due to the increased human activities. Herein, brewer's spent grain (BSG)-supported superabsorbent polymers (SAP) with different cross-linking densities are prepared as cheap and eco-friendly adsorbents for the first time via one-pot swelling and graft polymerization. A 7 wt% NaOH solution is used to swell BSG before grafting and subsequently neutralize the acrylic acid to control the reaction rate without producing alkaline wastewater. Compared with the traditional methods, swelling improves the grafting density and the utilization of raw materials due to the increased disorder degree of the BSG fibers. This results in the grafting of abundant carboxyl and amide groups onto the BSG backbone, forming a strongly hydrophilic polymer network of the BSG-SAP. Compared with the reference polymers without BSG, BSG-SAP presents higher adsorption capacity and enhanced reusability. The highly cross-linked BSG-SAP (BSG-SAP-H) shows an outstanding adsorption capacity of U(VI) (1465 mg/g at pH 0  = 4.6), a fast adsorption rate (81% of equilibrium adsorption capacity in 15 min), and a high selectivity in the presence of competing ions. Adsorption mechanism studies reveal the involvement of amide groups, a bidentate binding structure between UO 2 2+ and the carboxyl groups, and a cation exchange between Na + and UO 2 2+ . More importantly, the adsorption capacity of BSG-SAP-H reaches 254.4 mg/g in the fixed-bed column experiment at a low initial concentration (c 0 (U) = 30 mg/L) and keeps 80% of the adsorption capacity after four cycles, indicating a great potential for uranium removal from wastewater. This work shows a suitable approach to explore the untreated biomass to prepare SAP with enhanced adsorption performance via a general and low-cost strategy., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Crystal structure data for potassium orthoselenate(IV), K 2 SeO 3 , are reported for the first time. Colorless, block-shaped crystals were grown in a potassium hydro-flux, i.e. under ultra-alkaline conditions, within 10 h. K 2 SeO 3 crystallizes isostructural with Na 2 SO 3 and K 2 TeO 3 in the trigonal space group P with lattice parameters a = 6.1063 (4) Å and c = 6.9242 (4) Å at 100 (1) K. In the trigonal-pyramidal, C 3v -symmetric [SeO 3 ] 2- anion, the bond length is 1.687 (1) Å, and the bond angle is 103.0 (1)°. Two of the three unique potassium cations exhibit a coordination number of six, and the third a coordination number of nine., (© Albrecht et al. 2022.)

Single crystals of LaTe 1.9 (lanthanum telluride) have been obtained by chemical transport reactions with iodine as transport agent. LaTe 1.9 adopts the CeSe 1.9 structure type and crystallizes in the space group P 4 2 / n with lattice parameters a = 10.1072 (3) Å and c = 18.2874 (6) Å. The crystal structure comprises an alternating stacking of puckered [LaTe] slabs and planar [Te] layers along [001]. The planar [Te] layer is dominated by dumbbell-shaped Te 2 2- anions along an isolated Te 2- anion and a vacancy. The Te 2 2- anions form an eight-membered ring enclosing the vacancy in the centre., (© Poddig and Doert 2022.)

Developing biosorbents derived from agro-industrial biomass is considered as an economic and sustainable method for dealing with uranium-contaminated wastewater. The present study explores the feasibility of oxidizing a representative protein-rich biomass, brewer's spent grain (BSG), to an effective and reusable uranyl ion adsorbent to reduce the cost and waste generation during water treatment. The unique composition of BSG favors the oxidation process and yields in a high carboxyl group content (1.3 mmol/g) of the biosorbent. This makes BSG a cheap, sustainable, and suitable raw material independent from pre-treatment. The oxidized brewer's spent grain (OBSG) presents a high adsorption capacity of U(VI) of 297.3 mg/g ( c 0 (U) = 900 mg/L, pH = 4.7) and fast adsorption kinetics (1 h) compared with other biosorbents reported in the literature. Infrared spectra (Fourier transform infrared), 13 C solid-state nuclear magnetic resonance spectra, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis were employed to characterize the biosorbents and reveal the adsorption mechanisms. The desorption and reusability of OBSG were tested for five cycles, resulting in a remaining adsorption of U(VI) of 100.3 mg/g and a desorption ratio of 89%. This study offers a viable and sustainable approach to convert agro-industrial waste into effective and reusable biosorbents for uranium removal from wastewater., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

The low temperature syntheses of AuTe 2 and Ag 2 Te starting from the elements were investigated in the ionic liquids (ILs) [BMIm]X and [P 66614 ]Z ([BMIm] + =1-butyl-3-methylimidazolium; X = Cl, [HSO 4 ] - , [P 66614 ] +  = trihexyltetradecylphosphonium; Z = Cl - , Br - , dicyanamide [DCA] - , bis(trifluoromethylsulfonyl)imide [NTf 2 ] - , decanoate [dec] - , acetate [OAc] - , bis(2,4,4-trimethylpentyl)phosphinate [BTMP] - ). Powder X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy revealed that [P 66614 ]Cl is the most promising candidate for the single phase synthesis of AuTe 2 at 200 °C. Ag 2 Te was obtained using the same ILs by reducing the temperature in the flask to 60 °C. Even at room temperature, quantitative yield was achieved by using either 2 mol % of [P 66614 ]Cl in dichloromethane or a planetary ball mill. Diffusion experiments, 31 P and 125 Te-NMR, and mass spectroscopy revealed one of the reaction mechanisms at 60 °C. Catalytic amounts of alkylphosphanes in commercial [P 66614 ]Cl activate tellurium and form soluble phosphane tellurides, which react on the metal surface to solid telluride and the initial phosphane. In addition, a convenient method for the purification of [P 66614 ]Cl was developed., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

The increasing concerns on uranium and rare earth metal ion pollution in the environment require sustainable strategies to remove them from wastewater. The present study reports an eco-friendly approach to convert a kind of protein-rich biomass, brewer's spent grain (BSG), into effective biosorbents for uranyl and rare earth metal ions. The employed method reduces the energy consumption by performing the hydrothermal treatment at a significantly lower temperature (150 °C) than conventional hydrothermal carbonization. In addition, with the aid of the Maillard reaction between carbohydrates and proteins forming melanoidins, further activation processes are not required. Treatment at 150 °C for 16 h results in an altered biosorbent (ABSG) with increased content of carboxyl groups (1.46 mmol g -1 ) and a maximum adsorption capacity for La 3+ , Eu 3+ , Yb 3+ (pH = 5.7) and UO 2 2+ (pH = 4.7) of 38, 68, 46 and 221 mg g -1 , respectively. Various characterization methods such as FT-IR, 13 C CP/MAS NMR, SEM-EDX and STA-GC-MS analysis were performed to characterize the obtained material and to disclose the adsorption mechanisms. Aside from oxygen-containing functional groups, nitrogen-containing functional groups also contribute to the adsorption. These results strongly indicate that mild hydrothermal treatment of BSG could be applied as a greener, low-cost method to produce effective adsorbents for uranyl and rare earth metal ion removal., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The two-dimensionally incommensurately modulated crystal structures of the compounds RETe 1.94(1) (RE = La, Pr, Nd) were investigated by single-crystal X-ray diffraction. The compounds crystallize in the tetragonal superspace group P4/n(αβ½)00(-βα½)00 (No. 85.2.58.2) with q 1 = αa*+βb*+½c* and q 2 = -βa*+αb*+½c* and share a common motif of an alternating stacking of a puckered [RETe] layer and a planar [Te] layer. This basic structural motif is observed for all reported compounds with unusually large anisotropic displacement parameters in the planar [Te] layer. Taking the modulation into account, a distortion from this perfect square planar net is noted along with vacancies in the planar [Te] layer. The distortion leads to the formation of different discrete anions, like Te 2- , Te 2 2- and Te 3 2- , similar to previously reported structures for REX 2-δ compounds (RE = trivalent rare earth metal, X = S, Se, Te). The Te-Te distances in the modulated [Te] layer are found in a narrow range as compared to those in the corresponding sulfides and selenides., (open access.)

Invited for this month's cover is the group of Michael Ruck and Thomas Doert at the Technische Universität Dresden (Germany). The cover picture shows the transformation of a Bi-Ni core-shell particle into a homogenous intermetallic BiNi particle. To understand the mechanism for the BiNi formation in the polyol process, various methods such as X-ray and electron diffraction, HR-TEM, mass spectrometry and FT-IR spectroscopy were employed. In a microwave-assisted one-pot synthesis at first Bi-particles emerge by reduction of a Bi-salt. The reduction of the Ni-salt most likely occurs on the surface of these particles, followed by a complete encasement of the Bi-core (blue) with a shell of Ni-particles (green). As the reaction continues, the Ni-atoms diffuse into the Bi-core until the homogeneous BiNi particle is attained. Read the full text of their Full Paper at 10.1002/open.202000236., (© 2020 Wiley‐VCH GmbH.)

Single-crystals of thallium(I) iodide oxide Tl 3 IO were obtained as by-product in a hydro-flux synthesis at 473 K for 10 h. A potassium hydroxide hydro-flux with a water-base molar ratio of 1.6 and the starting materials TlNO 3 , RhI 3 and Ba(NO 3 ) 2 was used, resulting in a few black needle-shaped crystals. X-ray diffraction on a single-crystal revealed the hexa-gonal space group P 6 3 / mmc (No. 194) with lattice parameters a = 7.1512 (3) Å and c = 6.3639 (3) Å. Tl 3 IO crystallizes as hexa-gonal anti-perovskite (anti-BaNiO 3 type) and is thus structurally related to the alkali-metal halide/auride oxides M 3 X O ( M = K, Rb, Cs; X = Cl, Br, I, Au). The oxygen atoms center thallium octa-hedra. The [OTl 6 ] octa-hedra share trans faces, forming a linear chain along [001]. Twelve thallium atoms surround each iodine atom in an [ITl 12 ] anti-cubocta-hedron. Thallium and iodine atoms together form a hexa-gonal close-sphere packing, in which every fourth octa-hedral void is occupied by oxygen., (© Albrecht et al. 2020.)

SnSb alloy, which can be used as an anode in a sodium-ion cell, was synthesized following a resource-efficient route at low temperature. This one-pot approach greatly reduces the energy consumption and maximizes the efficient use of raw materials. The reaction of elemental tin and antimony in the ionic liquid (IL) trihexyltetradecylphosphonium chloride ([P 66614 ]Cl) at 200 °C led to a microcrystalline powder of single-phase SnSb within 10 h with very high yield (95%). Liquid-state nuclear magnetic resonance spectroscopy revealed that the IL remains essentially stable during the reaction. It was recovered almost quantitatively by distilling off the organic solvent used for product separation. Composites of SnSb powder and carbon nanotubes (CNTs) were fabricated by a simple ball milling process. Electrochemical measurements demonstrate that the Na‖SnSb/CNTs cell retains close to 100% of its initial capacity after 50 cycles at a current of 50 mA g -1 , which is much better than the Na‖SnSb cell. The greatly increased capacity retainability can be attributed to the conductive network formed by CNTs inside the SnSb/CNTs electrode, providing 3D effective and fast electronic pathways during sodium intercalation and de-intercalation., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)