Photocatalytic properties of CoOx-loaded nano-crystalline perovskite oxynitrides ABO2N (A = Ca,Sr, Ba,La; B = Nb,Ta)

Highly crystalline niobium- and tantalum-based oxynitride perovskite nanoparticles were obtained from hydrothermally synthesized oxide precursors by thermal ammonolysis at different temperatures. The samples were studied with respect to their morphological, optical and thermal properties as well as their photocatalytic activity in the decomposition of methyl orange. Phase pure oxynitrides were obtained at rather low ammonolysis temperatures between 740 °C (CaNbO₂N) and 1000 °C (BaTaO₂N). Particle sizes were found to be in the range 27 nm–146 nm and large specific surface areas up to 37 m² g⁻¹ were observed. High photocatalytic activities were found for CaNbO₂N and SrNbO₂N prepared at low ammonolysis temperatures. CoO_x as co-catalyst was loaded on the oxynitride particles resulting in a strong increase of the photocatalytic activities up to 30% methyl orange degradation within 3 h for SrNbO₂N:CoO_x.     

A Porous 4d–4f Heterometallic Coordination Polymer: Synthesis,Crystal Structure and Physical Properties

A 4d–4f heterometallic coordination polymer, [AgLa(pydc)₂]·3H₂O ( 1 ) (H₂pydc = pyridine‐3,4‐dicarboxylic acid), has been synthesized under hydrothermal conditions, and further characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction. Complex 1 features a three‐dimensional (3D) framework containing one‐dimensional (1D) channels occupied by free water molecules, which is constructed from 1D inorganic heterometallic chains and linear pydc linkers. To the best of our knowledge, complex 1 represents a rare example of 3D open‐framework 4d–4f heterometallic coordination polymer. Moreover, after removal of the water molecules from complex 1 , the remaining material has high thermal stability and good adsorption behavior towards nitrogen gas.     

Synthesis,Structure, and Properties of Nonlinear Optical Crystal Na2SiF6

Nonlinear optical crystals of fluosilicate Na₂SiF₆ are synthesized via hydrothermal method and its structure is determined by single‐crystal X‐ray diffraction (XRD). The space group of Na₂SiF₆ is P321 with cell parameters a = 8.8715(3) Å, c = 5.0484(5) Å, Z = 3, V = 344.09(4) ų. The properties of the crystal are measured by powder XRD, infrared (IR) spectroscopy, ultraviolet/visible (UV/Vis) near‐infrared (NIR) diffuse reflectance spectroscopy, thermogravimetric (TG), and differential scanning calorimetry (DSC) analysis. The bandgap calculated using CASTEP is 7.41 eV, indicating that the cut‐off edge of the Na₂SiF₆ crystal can be down to deep‐UV energy region. The first‐principles studies were performed to elucidate the structure/property relationship of Na₂SiF₆.     

On the High‐temperature Crystal Structure of Sr/Mg‐doped Lanthanum Gallate. Evidence for the First Perovskite‐type Structure with R3¯m Symmetry

The high temperature structure above 700 °C of the oxygen superionic conductor La_0.9Sr_0.1Ga_0.8Mg_0.2O_2.85 has been analyzed by means of a combined neutron and high resolution synchrotron powder study. The splitting of reflections and the absence of any superstructure reflections leads to the conclusion that the correct space group is R3¯m. This is the first example of this space group appearing within the subgroup family of the ideal parent perovskite structure with Pm3¯m symmetry.     

Synthesis,Crystal Structure and Properties of RbMnO2

RbMnO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursers (Mn₂O₃, RbN₃ and RbNO₃) were heated in a special regime up to 600 °C and annealed at this temperature for 30 h in specially designed silver crucibles. Single crystals have been grown by annealing a 1:1 mixture of Rb₂O and MnO_x at 585 °C for 1200 h. According to the crystal structure determination Mn³⁺ is in a square‐pyramidal coordination by oxygen. These [MnO₅] units form double chains extending along the crystallographic c‐axis. RbMnO₂ shows Curie‐Weiss behaviour down to ～ 100 K. A fit of the susceptibility data yields an average value of the magnetic moment (per manganese atom) of μ_eff = 5.33 μ_B, and θ_p = –820 K. At 50 K and low field strength onset of ferromagnetic order due to spin canting has been observed.     

亚甲基蒽苯乙烯吡啶盐的合成、结构及双光子吸收性质

以氯化4-甲基-N-9-亚甲基蒽吡啶盐为原料,合成了一种新型的苯乙烯吡啶盐,通过红外、核磁共振氢谱、碳谱、电喷雾质谱、单晶X射线衍射等测试技术对化合物的结构进行了表征。单晶X射线衍射结果表明,该化合物属于单斜晶系,空间群为P21/c,晶胞参数a=1.255 7(1)nm,b=1.539(1)nm,c=2.220 2(8)nm,β=101.099(1)°,V=4.210 5(4)nm3,Z=4,Dc=1.159 g/cm3。用1 064 nm皮秒脉冲激光研究其三阶非线性光学特性,双光子吸收系数β=0.028 cm/GW,吸收截面为σ=8.68×10-48cm4.s.photon-1,表明目标化合物具有良好的三阶非线性光学性质。     

Synthesis,Crystal Structure and Lithium Motion of Li8SeN2 and Li8TeN2

The compounds Li₈EN₂ with E = Se, Te were obtained in form of orange microcrystalline powders from reactions of Li₂E with Li₃N. Single crystal growth of Li₈SeN₂ additionally succeeded from excess lithium. The crystal structures were refined using single‐crystal X‐ray diffraction as well as X‐ray and neutron powder diffraction data (I4₁md, No. 109, Z = 4, Se: a = 7.048(1) Å, c = 9.995(1) Å, Te: a = 7.217(1) Å, c = 10.284(1) Å). Both compounds crystallize as isotypes with an anionic substructure motif known from cubic Laves phases and lithium distributed over four crystallographic sites in the void space of the anionic framework. Neutron powder diffraction pattern recorded in the temperature range from 3 K to 300 K and X‐ray diffraction patterns using synchrotron radiation taken from 300 K to 1000 K reveal the structural stability of both compounds in the studied temperature range until decomposition. Motional processes of lithium atoms in the title compounds were revealed by temperature dependent NMR spectroscopic investigations. Those are indicated by significant changes of the ⁷Li NMR signals. Lithium motion starts for Li₈SeN₂ above 150 K whereas it is already present in Li₈TeN₂ at this temperature. Quantum mechanical calculations of NMR spectroscopic parameters reveal clearly different environments of the lithium atoms determined by the electric field gradient, which are sensitive to the anisotropy of charge distribution at the nuclear sites. With respect to an increasing coordination number according to 2 + 1, 3, 3 + 1, and 4 for Li(3), Li(4), Li(2), and Li(1), respectively, the values of the electric field gradients decrease. Different environments of lithium predicted by quantum mechanical calculations are confirmed by ⁷Li NMR frequency sweep experiments at low temperatures.     

含2，2′-联吡啶配体簇合物的合成、晶体结构及非线性光学性质

The Cluster compound [Cu₃BrWOS₃(bipy)₂] was synthesized by reaction of (NH₄)₂WOS₃， CuBr， 2，2′- bipyridine and n-Bu₄NBr at room temperature and characterized by IR， UV and elemental analyses. The structure of [Cu₃BrWOS₃(bipy)₂] was determined by single crystal X-ray diffraction revealing that the cluster consist of a nest -shaped core. The W atom is tetrahedrally coordinated by three S atoms and one O atom. There are two types of copper atoms in the WOS₃Cu₃ aggregate： two copper atoms are tetrahedrally coordinated and another copper atom is trigonally coordinated. The nonlinear optical properties were studied with an 8ns pulsed laser at 532nm. Its optical responses to the incident light exhibit considerably optical absorptive and strong self-focusing effect with α₂=0.90×10^-10m·W^-1， n₂=2.72×10^-18m²·W^-1. CCDC： 196348.     

Synthesis and Crystal Structure of BaLaSi2H0.80

The polyanionic compound BaLaSi₂ featuring cis-trans silicon chains takes up hydrogen to form a hydride BaLaSi₂H_0.80. The crystal structure of the parent intermetallic compound is largely retained upon hydrogenation with the same space group type, a unit cell volume increase of 3.29 % and very similar atomic positions in the hydride. Hydrogen could be located in the crystal structure by neutron diffraction on the deuteride. Deuterium atoms occupy a tetrahedral Ba₃La interstitial with 40.6(2) % occupation (Cmcm, a = 464.43(4) pm, b = 1526.7(1) pm, c = 676.30(6) pm). BaLaSi₂H_0.80 is thus an interstitial Zintl phase hydride like LaSiH_1–x, but unlike BaSiH_2–x does not feature any covalent Si–H bonds. Si–Si distances within the polyanion increase upon hydrogenation from 240.1(6) and 242.9(5) pm to 244.7(2) pm and 245.5(2) pm. This is probably due to oxidation of the polyanion by hydrogen, which leads to the formation of hydride ions and the depopulation of the polyanion's antibonding π* states. Interatomic Ba–D [260.9(4) pm, 295.7(5) pm] and La–D distances [241.2(7) pm] are in the typical range of ionic hydrides.     

Synthesis,Crystal Structure and Properties of Na2MnO2

Na₂MnO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Mn₂O₃, NaN₃ and NaNO₃) were heated in an appropriate regime up to 390 °C and annealed at this temperature for 20 h, in specially designed silver containers. As the most prominent feature, the crystal structure of Na₂MnO₂ (C2/c, Z = 12, a = 12.5026(9), b = 12.1006(9), c = 6.0939(4) Å, β = 117.94(0)°, 1556 independent reflections, R₁ = 3.83 % (all data)) forms a three dimensional framework polyanion of corner sharing MnO₄‐tetrahedra. The connectivity pattern of the tetrahedral building units corresponds to the moganite structure, a rare SiO₂ modification. According to measurements of the magnetic susceptibility in the temperature range from 2 to 750 K, Na₂MnO₂ shows antiferromagnetic ordering below 250 K. Evaluation of the high temperature data employing the Curie‐Weiss law revealed a magnetic moment of μ_eff = 5.93 μ_B, confirming the presence of divalent manganese.     

一种芴酮衍生物的合成、晶体结构及其光限幅性能

一种芴酮衍生物的合成、晶体结构及其光限幅性能;芴酮衍生物; 单晶结构; 光限幅性能     

Synthesis and Crystal Structure of Rubidium Lanthanum Tetraacetate,RbLa(CH3COO)4

The anhydrous rubidium tetraacetato lanthanate, RbLa(CH₃COO)₄, is obtained together with Rb₂La(CH₃COO)₅(H₂O) as colourless single crystals from a 1 : 2 mixture of Rb₂CO₃ and La(CH₃COO) · 1.5 H₂O in acetic acid by slow evaporation. The crystal structure [orthorhombic, Pnnm, Z = 2, a = 1242.0(3), b = 1650.1(4), c = 698.0(4) pm, R = 0.028, R_w = 0.071] contains La³⁺ nine coordinate by oxygen atoms of six acetate ligands. The polyhedra are connected to dimers and further to double chains running parallel to [001]. These [La(CH₃COO)₄]^– double chains are surrounded by four like double chains and connected by Rb⁺ ions that are seven coordinate by oxygen atoms.     

Chemical Synthesis,Structure Characterization,and Optical Properties of Hollow PbSx–Solid Au Heterodimer Nanostructures

Heterodimer nanostructures have attracted extensive attention, owing to an increasing degree of complexity, functionality, and then importance. So far, all the reported ones are built from solid nanoparticles. Herein, nearly monodisperse heterodimer nanostructures are constructed by hollow PbS_x and solid Au domains simultaneously through a mild reaction between PbS nanocrystals and the gold species in the presence of dodecylamine. Control experiments clearly reveal the underlying formation mechanism of the hollow PbS_x–solid Au heterodimers. The Au^III species in the solution, lead to the etching of PbS nanocrystals and the Au^I species facilitate the control of the number of gold domains per nanoparticle. Dodecylamine molecules not only work as a stabilizer in the reaction, but also act as a reducing agent that could greatly affect the morphology of the product. The optical properties of the heterodimers are investigated based on UV/Vis absorption spectroscopy and Raman spectroscopy. This novel heterodimer nanostructure pushes the development of complex nanocrystal‐based architectures forward, and also provides many opportunities for potential applications.     

Synthesis,Crystal Structure and Optical Properties of KPr（MoO4）2 with the Scheelite-type Structure

Solid-state reaction of praseodymium （III） oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr（MoO4）2. The structural and optical properties of the title compound have been investigated by means of single-crystal X-ray diffraction and spectroscopic measurements at room temperature. KPr（MoO4）2 crystallizes in tetragonal,space group I41/a with a = 5.401（3）,c = 12.044（10）,Z = 2 and R （I 〉 2σ（I）） = 0.0416. It features the famous scheelite-type structure （CaWO4）,which can be thought as the substitution of two Ca^2＋ ions in CaWO4 by a couple of K^＋ and Pr^3＋ ions in a statistical manner,and W^6＋ by Mo^6＋ cations.     

MXenes as Emerging Materials: Synthesis,Properties, and Applications

Due to their unique layered microstructure, the presence of various functional groups at the surface, earth abundance, and attractive electrical, optical, and thermal properties, MXenes are considered promising candidates for the solution of energy- and environmental-related problems. It is seen that the energy conversion and storage capacity of MXenes can be enhanced by changing the material dimensions, chemical composition, structure, and surface chemistry. Hence, it is also essential to understand how one can easily improve the structure–property relationship from an applied point of view. In the current review, we reviewed the fabrication, properties, and potential applications of MXenes. In addition, various properties of MXenes such as structural, optical, electrical, thermal, chemical, and mechanical have been discussed. Furthermore, the potential applications of MXenes in the areas of photocatalysis, electrocatalysis, nitrogen fixation, gas sensing, cancer therapy, and supercapacitors have also been outlooked. Based on the reported works, it could easily be observed that the properties and applications of MXenes can be further enhanced by applying various modification and functionalization approaches. This review also emphasizes the recent developments and future perspectives of MXenes-based composite materials, which will greatly help scientists working in the fields of academia and material science.     

Synthesis, Crystal Structure and Electrochemical Properties of 2-Chlorobenzaldehyde Thiosemicarbazone

Recently,tremend0useffortshavebeendevotedtosynthesisof0rgan0metalliccomp0undswithlargesecondorder0pticaln0nlinearities."2'3H0wever,fewofthemcanbeusedasapplicablematerials,owingtotheintensecolorofmosttransitionmetalcomplexes.Andwef0undthatthatpalecolormetalcomplexesderivedfromthiosemicarbazonemightbethepossiblewaytoobtainthenonlinearopticalcompoundwhichcouldbeusedasaPplicablematerials.InthispaPer,2-chlorobenzaldehydethiosemicarbazoneligandhasbeendesignedandsynthesized,thecomplexofcadmiumbromid…     

Synthesis and Crystal Structure of LiZn13

By simultaneous deposition of zinc and lithium onto a cooled sapphire substrate, LiZn₁₃ was obtained for the first time. It crystallizes in the NaZn₁₃ structure type (Fmc, a = 1234.92(6) pm, R_p = 5.4 %, R_wp = 6.9 %, structure analysis with the Rietveld‐method). Single‐phase LiZn₁₃ forms from a hexagonal Li_0.07Zn_0.93 alloy, deposited at –196 °C, during heating up to room temperature. Above room temperature LiZn₁₃ decomposes.     

The Metallic Zintl Phase Ba3Si4 – Synthesis,Crystal Structure,Chemical Bonding,and Physical Properties

The Zintl phase Ba₃Si₄ has been synthesized from the elements at 1273 K as a single phase. No homogeneity range has been found. The compound decomposes peritectically at 1307(5) K to BaSi₂ and melt. The butterfly‐shaped Si₄⁶⁻ Zintl anion in the crystal structure of Ba₃Si₄ (Pearson symbol tP28, space group P4₂/mnm, a = 8.5233(3) Å, c = 11.8322(6) Å) shows only slightly different Si‐Si bond lengths of d(Si–Si) = 2.4183(6) Å (1×) and 2.4254(3) Å (4×). The compound is diamagnetic with χ ≈ −50 × 10⁻⁶ cm³ mol⁻¹. DC resistivity measurements show a high electrical resistivity (ρ(300 K) ≈ 1.2 × 10⁻³ Ω m) with positive temperature gradient dρ/dT. The temperature dependence of the isotropic signal shift and the spin‐lattice relaxation times in ²⁹Si NMR spectroscopy confirms the metallic behavior. The experimental results are in accordance with the calculated electronic band structure, which indicates a metal with a low density of states at the Fermi level. The electron localization function (ELF) is used for analysis of chemical bonding. The reaction of solid Ba₃Si₄ with gaseous HCl leads to the oxidation of the Si₄⁶⁻ Zintl anion and yields nanoporous silicon.