Crystals

13 pages, 7472 KiB

Open AccessArticle

Effects of Matrix Silicon Content on the Plasma Electrolytic Oxidation of Al-Si Alloys Using Different Power Modes

by Kang Li, Guoge Zhang, Aihua Yi, Wen Zhu, Zhongmiao Liao, Ken Chen, Wenfang Li and Zhenyuan Luo

Crystals 2022, 12(1), 123; https://doi.org/10.3390/cryst12010123 - 17 Jan 2022

Cited by 3 | Viewed by 1978

Abstract

The plasma electrolytic oxidation (PEO) of pure Al and Al alloys containing 4, 9, 12, or 15 wt.% Si were investigated under pulsed bipolar current and pulsed bipolar voltage modes, respectively. It was determined that the discharge sparks preferentially occurred on the SiO [...] Read more.

The plasma electrolytic oxidation (PEO) of pure Al and Al alloys containing 4, 9, 12, or 15 wt.% Si were investigated under pulsed bipolar current and pulsed bipolar voltage modes, respectively. It was determined that the discharge sparks preferentially occurred on the SiO₂ relative to the Al₂O₃ during the initial stage of PEO processing regardless of the power mode. Following 30 min of PEO treatment under the two modes, the thicknesses of the layers decreased, whereas their specific energy consumption increased with increasing Si content in the matrix. The presence of primary Si in the alloy with 15 wt.% Si had a significantly negative effect on the PEO process in the pulsed bipolar current mode: The layer thickness decreased by 45%, and its specific energy consumption increased by 52%, compared with those on pure Al. However, in the pulsed bipolar voltage mode, the layer thickness on the evaluated samples only decreased slightly, and it became much more similar after treatment. Full article

(This article belongs to the Special Issue Nanocrystalline Coating Alloy)

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13 pages, 3739 KiB

Open AccessArticle

The Chemical Composition of Trapiche-like Quartz from Huanggangliang Area, Inner Mongolia, China

by Ling Jiang, Zhu Chen and Yingxin Liu

Crystals 2022, 12(1), 122; https://doi.org/10.3390/cryst12010122 - 17 Jan 2022

Cited by 2 | Viewed by 2528

Abstract

Trapiche-like quartz, which is found in Huanggangliang area, Chifeng City, Inner Mongolia, China, has a short columnar euhedral shape. Arms of trapiche-like phenomena are formed by six radial dark bands located along the a-axis of crystals, and their cores are formed by [...] Read more.

Trapiche-like quartz, which is found in Huanggangliang area, Chifeng City, Inner Mongolia, China, has a short columnar euhedral shape. Arms of trapiche-like phenomena are formed by six radial dark bands located along the a-axis of crystals, and their cores are formed by color zones. Various methods were used to investigate the conventional gemological characteristics, trapiche pattern features, chemical compositions, and spectral characteristics of the trapiche-like quartz. CL images and EPMA results reveal they were formed at high temperature conditions and originated from pegmatite. The hexagonal darker zones with high FeO and very little TiO₂ contents indicate the trapiche-like patterns are due to spatial distribution of color-inducing elements. According to the position and interpenetration relationship between inclusions, fibrous and spherical inclusions are identified as protogenetic inclusions, which were respectively identified to be ferro-actinolite and iron oxide by EPMA and Raman spectra. Full article

(This article belongs to the Special Issue Gem Crystals)

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13 pages, 13398 KiB

Open AccessArticle

Magnetic Properties of FeNiCoAlTiNb Shape Memory Alloys

by Chau-Yi Tsai, Li-Wei Tseng, Yu-Chih Tzeng and Po-Yu Lee

Crystals 2022, 12(1), 121; https://doi.org/10.3390/cryst12010121 - 17 Jan 2022

Cited by 5 | Viewed by 1987

Abstract

The magnetic properties of the new Fe₄₁Ni₂₈Co₁₇Al_11.5(Ti+Nb)_2.5 (at. %) shape memory alloy system were studied in this work. The magnetic properties were characterized by thermo-magnetization and a vibrating sample magnetometer (VSM). In iron-based shape [...] Read more.

The magnetic properties of the new Fe₄₁Ni₂₈Co₁₇Al_11.5(Ti+Nb)_2.5 (at. %) shape memory alloy system were studied in this work. The magnetic properties were characterized by thermo-magnetization and a vibrating sample magnetometer (VSM). In iron-based shape memory alloys, aging heat treatment is crucial for obtaining the properties of superelasticity and shape memory. In this study, we focus on the magnetization, martensitic transformation temperatures, and microstructure of this alloy during the aging process at 600 °C. From the X-ray diffraction (XRD) results, the new peak γ’ is presented during the aging process. The intensity of this new peak (γ’) increases with the aging time, while the intensity of the FCC (111) austenite peak decreases with aging time. Transmission electron microscope (TEM) results show that the size of the precipitate increases with increasing the aging times from 24 to 72 h. Thermo-magnetization results show that: (1) phase transformation is observed when the aging time is at least 24 h, (2) the transformation temperature increases with the aging time, (3) transformation temperatures tend to increase while the magnetic field increases from 0.05 to 7 Tesla, and (4) the magnetization saturates after aging time reaches 24 h. Vibrating sample magnetometer (VSM) results show that thermal process was found to significantly affect the magnetic properties of this alloy, especially on saturated magnetic magnetization and magnetic moment reversal behavior. Full article

(This article belongs to the Special Issue Application of Shape Memory Alloys)

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12 pages, 21287 KiB

Open AccessArticle

Luminescence Properties of Gd₂(MoO₄)₃ Modified with Sm(III) and Tb(III) for Potential LED Applications

by Martin Tsvetkov, Denitsa Elenkova and Maria Milanova

Crystals 2022, 12(1), 120; https://doi.org/10.3390/cryst12010120 - 17 Jan 2022

Cited by 8 | Viewed by 2022

Abstract

Light-emitting phosphors, doped with lanthanide ions of Tb(III) and Sm(III) of the type Gd_1.97−y Sm_yTb_0.03(MoO₄)₃ (y = 0.01–0.11, step 0.02) and Gd_1.95−xSm_0.05Tb_x(MoO₄)₃ (x = 0.01–0.09, step [...] Read more.

Light-emitting phosphors, doped with lanthanide ions of Tb(III) and Sm(III) of the type Gd_1.97−y Sm_yTb_0.03(MoO₄)₃ (y = 0.01–0.11, step 0.02) and Gd_1.95−xSm_0.05Tb_x(MoO₄)₃ (x = 0.01–0.09, step 0.02), were synthesized and characterized by X-ray diffraction, UV-Vis spectroscopy, scanning and transmitting electron microscopy (SEM, TEM) as well as photoluminescence spectroscopy. The effect of the doping content of Tb/Sm was followed. The unit cell parameters for Gd_1.97−ySm_yTb_0.03(MoO₄)₃ and Gd_1.95−xSm_0.05Tb_x(MoO₄)₃ changed with the increase in the Tb/Sm content. The microstrain values also increased, proposing an increased concentration of defects. The mean particle size was estimated to be approximately 0.6 µm. Based on a Williamson–Hall plot, the size of the crystallites was determined to be in the range of 42–60 nm for modified and pure Gd₂(MoO₄)₃ samples, respectively. The samples excited at 406 nm exhibited characteristic emission lines of Sm (485, 555, 646 nm). The host material Gd₂(MoO₄)₃ emission in visible light was explained by the crystal structure defects, namely, oxygen vacancies. The CIE x/y color coordinates of the phosphors were determined and the related points were located in the green-yellow/pale yellow region of the visible light. The excited state lifetimes were determined for both groups of the samples, showing values in the millisecond range and indicating the samples as promising phosphors. Full article

(This article belongs to the Special Issue Rare Earths-Doped Materials)

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12 pages, 4118 KiB

Open AccessArticle

Shock Properties of One Unsaturated Clay and Its Equation of State Up to 30 GPa

by Xianwen Ran, Xuan Zou, Jingyuan Zhou and Wenhui Tang

Crystals 2022, 12(1), 119; https://doi.org/10.3390/cryst12010119 - 17 Jan 2022

Cited by 1 | Viewed by 1548

Abstract

The complicated composition of unsaturated clay, e.g., solid mineral particles, water, and air, makes it difficult to get its precise equation of state (EOS) over a wide pressure range. In this paper, the high-pressure EOS of unsaturated clay was discussed at the mesoscale. [...] Read more.

The complicated composition of unsaturated clay, e.g., solid mineral particles, water, and air, makes it difficult to get its precise equation of state (EOS) over a wide pressure range. In this paper, the high-pressure EOS of unsaturated clay was discussed at the mesoscale. With the original clay extracted from the southern suburbs of Luoyang city, China, three unsaturated clays with moisture contents of 0%, 8%, and 15%, respectively, were remolded. Their Hugoniot parameters in the pressure range of 0–30 GPa were measured using a one-stage or two-stage light gas gun. With the measured Hugoniot parameters, a high-pressure EOS of the unsaturated clay up to 30 GPa was developed and it is in good agreement with the experimental data. Full article

(This article belongs to the Special Issue Dynamic Behavior of Materials)

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15 pages, 7613 KiB

Open AccessArticle

Sorption of Acridine Orange on Non-Swelling and Swelling Clay Minerals

by Wei-Teh Jiang, Yolin Tsai, Xisen Wang, Hannah J. Tangen, Jessica Baker, Lori Allen and Zhaohui Li

Crystals 2022, 12(1), 118; https://doi.org/10.3390/cryst12010118 - 17 Jan 2022

Cited by 7 | Viewed by 1824

Abstract

Acridine orange (AO) is a cationic fluorescent dye commonly used in DNA analyses. Extensive studies were conducted for its metachromasy under different solution concentrations and different amounts of AO sorbed on a solid surface. Meanwhile, for the safe disposal of wastewater, AO removal [...] Read more.

Acridine orange (AO) is a cationic fluorescent dye commonly used in DNA analyses. Extensive studies were conducted for its metachromasy under different solution concentrations and different amounts of AO sorbed on a solid surface. Meanwhile, for the safe disposal of wastewater, AO removal from water using different materials was also evaluated extensively. Clay minerals, due to their large specific surface area, high cation exchange capacity, and vast reserves, have been evaluated as potential sorbents for the removal of a variety of different types of contaminants, including color dyes. In this study, the sorption of AO on different types of clay minerals was contrasted. The sorption of co-presenting Zn²⁺ was much less than the sorption of AO, suggesting that clay minerals have higher affinities for AO in comparison to inorganic Zn²⁺. The desorption of exchangeable cations was linearly related to AO sorption, and the amounts of AO sorbed were close to the CEC values of the minerals, confirming that cation exchange is the dominating mechanism for AO sorption. Molecular dynamics simulation results showed that, under low and high AO loading levels, the sorbed AO formed monolayers and bilayers on the mineral surfaces of non-swelling clay minerals, except halloysite, as well as in the interlayer of swelling clay minerals, due to its relatively large dimer constant in solution. Overall, clay minerals are good candidates for the removal of cationic dyes from solution even in the presence of competing inorganic cations. Full article

(This article belongs to the Section Hybrid and Composite Crystalline Materials)

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8 pages, 2338 KiB

Open AccessArticle

The Influence of Ion Beam Bombardment on the Properties of High Laser-Induced Damage Threshold HfO₂ Thin Films

by Yingxue Xi, Jiwu Zhao, Jin Zhang, Changming Zhang and Qi Wu

Crystals 2022, 12(1), 117; https://doi.org/10.3390/cryst12010117 - 17 Jan 2022

Cited by 4 | Viewed by 1881

Abstract

HfO₂ thin films were deposited on BK-7 glass substrates using an electron beam evaporation deposition (EBD) technique and then post-treated with argon and oxygen ions at an ion energy ranging from 800 to 1200 eV. The optical properties, laser damage resistance, and [...] Read more.

HfO₂ thin films were deposited on BK-7 glass substrates using an electron beam evaporation deposition (EBD) technique and then post-treated with argon and oxygen ions at an ion energy ranging from 800 to 1200 eV. The optical properties, laser damage resistance, and surface morphology of the thin films exposed to Ar ions and O₂ ions at various energies were studied. It was found that the two ion post-treatment methods after deposition were effective for improving the LIDT of HfO₂ thin films, but the mechanism for the improvement differs. The dense thin films highly resistant to laser damage can be obtained through Ar ion post-treatment at a certain ion energy. The laser-induced damage threshold (LIDT) of thin films after O₂ ion post-treatment was higher in comparison to those irradiated with Ar ion at the same ion energy. Full article

(This article belongs to the Special Issue Photovoltaic Functional Crystals and Ceramics)

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19 pages, 8393 KiB

Open AccessArticle

Microwave Roasting Characteristics of Cuprous Chloride Residue from Zinc Hydrometallurgy

by Zhanyong Guo, Fachuang Li, Qian Zhang, Guang Su, Jun Chang and Huilin Zhou

Crystals 2022, 12(1), 116; https://doi.org/10.3390/cryst12010116 - 17 Jan 2022

Cited by 6 | Viewed by 1666

Abstract

High-efficiency dechlorination processes are crucial for the clean utilization of CuCl waste residue from zinc hydrometallurgical processes. A new method of oxygen-enriched microwave roasting has been proposed to improve the dechlorination process. The cavity perturbation method was used in this paper to measure [...] Read more.

High-efficiency dechlorination processes are crucial for the clean utilization of CuCl waste residue from zinc hydrometallurgical processes. A new method of oxygen-enriched microwave roasting has been proposed to improve the dechlorination process. The cavity perturbation method was used in this paper to measure the permittivity of a CuCl residue at various temperatures and apparent densities. The results show that temperature had a more significant effect on the loss tangent when it exceeded 400 °C more than that of apparent densities. The degree of dechlorination of CuCl residue exceeded 93% after 90 min of microwave roasting at 450 °C and 150 mL/min oxygen flow, which was 12% higher than that of conventional calcination. The elemental distribution in samples was studied using single-point, linear, and lateral scans at the microscale, and the microstructure and phase changes of the CuCl residue under a microwave field were characterized by XRD and SEM-EDS. This study shows that microwaves can promote the dechlorination reaction by decreasing the activation energy from 52.69 kJ/mol to 42.36 kJ/mol. Full article

(This article belongs to the Special Issue Metallurgical Slag)

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13 pages, 3396 KiB

Open AccessArticle

Nanosheet-Assembled MnO₂-Integrated Electrode Based on the Low-Temperature and Green Chemical Route

by Xiaoli Wang, Yin Wang and Xinyu Zhao

Crystals 2022, 12(1), 115; https://doi.org/10.3390/cryst12010115 - 16 Jan 2022

Cited by 5 | Viewed by 2113

Abstract

The development of superior electrochemical energy-storage devices designed through a facile, cost-efficient, and green synthesis technique is the key to addressing the intermittent nature of renewable energy sources such as solar and wind energy. In our present work, we design a simple, surfactant-free, [...] Read more.

The development of superior electrochemical energy-storage devices designed through a facile, cost-efficient, and green synthesis technique is the key to addressing the intermittent nature of renewable energy sources such as solar and wind energy. In our present work, we design a simple, surfactant-free, and low-temperature chemical strategy to prepare novel integrated, MnO₂ composite electrodes with two-dimensional (2D) nanosheet film directly supported on three-dimensional (3D) conductive nickel foam. Benefiting from the specific 2D nanosheet architecture to provide a large interfacial contact area and highly conductive metal scaffolds to facilitate fast electron transfer, the novel nanosheet-assembled MnO₂-integrated electrodes exhibit higher specific capacitance of 446 F g⁻¹ at the current density of 1 A g⁻¹ compared with nanostructured MnO₂ and commercial MnO₂ powder electrodes. More importantly, the as-synthesized devices are able to achieve an outstanding cycling performance of 95% retention after 3000 cycles. The present work, which is based on the low-temperature chemical route to deposit active materials on the conductive substrate, provides new insights into designing a binder-free supercapacitor system to improve the specific capacitance, cycling, and rate performance as next-generation, energy-storage devices. Full article

(This article belongs to the Special Issue Progress in Advanced Battery Materials)

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9 pages, 3713 KiB

Open AccessArticle

Optical Properties of InGaN/GaN QW with the Same Well-Plus-Barrier Thickness

by Huan Xu, Xin Hou, Lan Chen, Yang Mei and Baoping Zhang

Crystals 2022, 12(1), 114; https://doi.org/10.3390/cryst12010114 - 15 Jan 2022

Cited by 4 | Viewed by 2481

Abstract

Optical properties of wurtzite violet InGaN/GaN quantum well (QW) structures, with the same well-plus-barrier thickness, grown by metal-organic chemical vapor deposition (MOCVD) on c-plane sapphire substrates, were investigated using temperature-dependent photoluminescence (TDPL) and excitation-power-dependent photoluminescence (PDPL). Two samples were compared: one had a [...] Read more.

Optical properties of wurtzite violet InGaN/GaN quantum well (QW) structures, with the same well-plus-barrier thickness, grown by metal-organic chemical vapor deposition (MOCVD) on c-plane sapphire substrates, were investigated using temperature-dependent photoluminescence (TDPL) and excitation-power-dependent photoluminescence (PDPL). Two samples were compared: one had a thicker well (InGaN/GaN 3/5 nm); the other had a thicker barrier (InGaN/GaN 2/6 nm). It was found that the GaN barrier thickness in the InGaN/GaN MQWs plays an important role in determining the optical characteristics of the MQWs. The peak energy of the two samples varied with temperature in an S-shape. The thicker-barrier sample had a higher turning point from blueshift to redshift, indicating a stronger localization effect. From the Arrhenius plot of the normalized integrated PL intensity, it was found that the activation energy of the nonradiative process also increased with a thicker barrier thickness. The radiation recombination process was dominated in the sample of the thicker barrier, while the non-radiation process cannot be negligible in the sample of the thicker well. Full article

(This article belongs to the Special Issue Advances in GaN-Based Optoelectronic Materials and Devices)

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13 pages, 7380 KiB

Open AccessArticle

The Synthesis and Characterization of a Novel One-Dimensional Bismuth (III) Coordination Polymer as a Precursor for the Production of Bismuth (III) Oxide Nanorods

by Younes Hanifehpour, Babak Mirtamizdoust, Jaber Dadashi, Ruiyao Wang, Mahboube Rezaei, Mehdi Abdolmaleki and Sang Woo Joo

Crystals 2022, 12(1), 113; https://doi.org/10.3390/cryst12010113 - 15 Jan 2022

Cited by 5 | Viewed by 2588

Abstract

A novel Bi (III) coordination compound, [Bi(HQ)(Cl)₄]_n ((Q = pyridine-4-carbaldehyde thiosemicarbazone), was prepared in this research using a sonochemical technique. SEM, infrared spectroscopy (IR), XRD, and single-crystal X-ray analysis were utilized to analyze the Bi(III) coordination compound. The structure determined [...] Read more.

A novel Bi (III) coordination compound, [Bi(HQ)(Cl)₄]_n ((Q = pyridine-4-carbaldehyde thiosemicarbazone), was prepared in this research using a sonochemical technique. SEM, infrared spectroscopy (IR), XRD, and single-crystal X-ray analysis were utilized to analyze the Bi(III) coordination compound. The structure determined using single-crystal X-ray crystallography indicates that the coordination compound is a 1D polymer in solid state and that the coordination number of bismuth (III) ions is six, (BiSCl₅), with one S donor from the organic ligand and five Cl donors from anions. It is equipped with a hemidirectional coordination sphere. It is interesting that the ligand has been protonated in the course of the reaction with a Cl^- ion balancing the charge. This compound’s supramolecular properties are directed and regulated by weak directional intermolecular interactions. Through π–π stacking interactions, the chains interact with one another, forming a 3D framework. Thermolysis of the compound at 170 °C with oleic acid resulted in the formation of pure phase nanosized Bi (III) oxide. SEM technique was used to examine the morphology and size of the bismuth (III) oxide product produced. Full article

(This article belongs to the Special Issue Feature Papers in Organic Crystalline Materials)

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14 pages, 2879 KiB

Open AccessArticle

π-Hole Tetrel Bonds—Lewis Acid Properties of Metallylenes

by Sławomir J. Grabowski

Crystals 2022, 12(1), 112; https://doi.org/10.3390/cryst12010112 - 15 Jan 2022

Cited by 19 | Viewed by 2347

Abstract

The MP2/aug-cc-pVTZ calculations were performed on the dihalometallylenes to indicate their Lewis acid and Lewis base sites. The results of the Cambridge Structural Database search show corresponding and related crystal structures where the tetrel center often possesses the configuration of a trigonal bipyramid [...] Read more.

The MP2/aug-cc-pVTZ calculations were performed on the dihalometallylenes to indicate their Lewis acid and Lewis base sites. The results of the Cambridge Structural Database search show corresponding and related crystal structures where the tetrel center often possesses the configuration of a trigonal bipyramid or octahedron. The calculations were also carried out on dimers of dichlorogermylene and dibromogermylene and on complexes of these germylenes with one and two 1,4-dioxide molecules. The Ge⋯Cl, Ge⋯Br, and Ge⋯O interactions are analyzed. The Ge⋯O interactions in the above mentioned germylene complexes may be classified as the π-hole tetrel bonds. The MP2 calculations are supported by the results of the Quantum Theory of Atoms in Molecules (QTAIM) and the Natural Bond Orbital (NBO) approaches. Full article

(This article belongs to the Special Issue Theoretical Investigation on Non-covalent Interactions)

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11 pages, 9356 KiB

Open AccessEditor’s ChoiceArticle

Variation of Surface Nanostructures on (100) PbS Single Crystals during Argon Plasma Treatment

by Sergey P. Zimin, Nikolai N. Kolesnikov, Ildar I. Amirov, Viktor V. Naumov, Egor S. Gorlachev, Sara Kim and Nam-Hoon Kim

Crystals 2022, 12(1), 111; https://doi.org/10.3390/cryst12010111 - 15 Jan 2022

Cited by 2 | Viewed by 2224

Abstract

The nanostructuring of the (100) PbS single crystal surface was studied under varying argon plasma treatment conditions. The initial PbS single crystals were grown by high-pressure vertical zone melting, cut into wafer samples, and polished. Subsequently, the PbS single crystals were treated with [...] Read more.

The nanostructuring of the (100) PbS single crystal surface was studied under varying argon plasma treatment conditions. The initial PbS single crystals were grown by high-pressure vertical zone melting, cut into wafer samples, and polished. Subsequently, the PbS single crystals were treated with inductively coupled argon plasma under varying treatment parameters such as ion energy and sputtering time. Plasma treatment with ions at a minimum energy of 25 eV resulted in the formation of nanotips with heights of 30–50 nm. When the ion energy was increased to 75–200 eV, two types of structures formed on the surface: high submicron cones and arrays of nanostructures with various shapes. In particular, the 120 s plasma treatment formed specific cruciform nanostructures with lateral orthogonal elements oriented in four <100> directions. In contrast, plasma treatment with an ion energy of 75 eV for 180 s led to the formation of submicron quasi-spherical lead structures with diameters of 250–600 nm. The nanostructuring mechanisms included a surface micromasking mechanism with lead formation and the vapor–liquid–solid mechanism, with liquid lead droplets acting as self-forming micromasks and growth catalysts depending on the plasma treatment conditions (sputtering time and rate). Full article

(This article belongs to the Special Issue Multiscale Interactions between Surface Topographies, Their Functions and Formation Technologies for Crystalline Materials)

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6 pages, 869 KiB

Open AccessCommunication

Secondary Structure and X-ray Crystallographic Analysis of the Glideosome-Associated Connector (GAC) from Toxoplasma gondii

by Amit Kumar, Xu Zhang, Oscar Vadas, Fisentzos A. Stylianou, Nicolas Dos Santos Pacheco, Sarah L. Rouse, Marc L. Morgan, Dominique Soldati-Favre and Steve Matthews

Crystals 2022, 12(1), 110; https://doi.org/10.3390/cryst12010110 - 15 Jan 2022

Cited by 2 | Viewed by 2701

Abstract

A model for parasitic motility has been proposed in which parasite filamentous actin (F-actin) is attached to surface adhesins by a large component of the glideosome, known as the glideosome-associated connector protein (GAC). This large 286 kDa protein interacts at the cytoplasmic face [...] Read more.

A model for parasitic motility has been proposed in which parasite filamentous actin (F-actin) is attached to surface adhesins by a large component of the glideosome, known as the glideosome-associated connector protein (GAC). This large 286 kDa protein interacts at the cytoplasmic face of the plasma membrane with the phosphatidic acid-enriched inner leaflet and cytosolic tails of surface adhesins to connect them to the parasite actomyosin system. GAC is observed initially to the conoid at the apical pole and re-localised with the glideosome to the basal pole in gliding parasite. GAC presumably functions in force transmission to surface adhesins in the plasma membrane and not in force generation. Proper connection between F-actin and the adhesins is as important for motility and invasion as motor operation itself. This notion highlights the need for new structural information on GAC interactions, which has eluded the field since its discovery. We have obtained crystals that diffracted to 2.6–2.9 Å for full-length GAC from Toxoplasma gondii in native and selenomethionine-labelled forms. These crystals belong to space group P2₁2₁2₁; cell dimensions are roughly a = 119 Å, b = 123 Å, c = 221 Å, α = 90°, β = 90° and γ = 90° with 1 molecule per asymmetric unit, suggesting a more compact conformation than previously proposed Full article

(This article belongs to the Special Issue Crystallographic Studies of Enzymes (Volume II))

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9 pages, 2370 KiB

Open AccessArticle

Spectroscopic and Surface Crystallization Characterizations of Yttrium-Doped Phosphate Glasses

by Haijian Li, Hao Zou, Zhihua Sun, Yi Xu, Changjian Wang, Xiao Xie, Jianhua Yi and Fengqi Zhao

Crystals 2022, 12(1), 109; https://doi.org/10.3390/cryst12010109 - 14 Jan 2022

Cited by 3 | Viewed by 1979

Abstract

The composition, structure, and thermal behaviors of yttrium-containing phosphate glasses were studied in this work, and the glass-ceramics were prepared via the two-step crystallization method. The XRD and SEM-EDS results show the forming range of the phosphate glass system and the formation of [...] Read more.

The composition, structure, and thermal behaviors of yttrium-containing phosphate glasses were studied in this work, and the glass-ceramics were prepared via the two-step crystallization method. The XRD and SEM-EDS results show the forming range of the phosphate glass system and the formation of YPO₄ (xenotime) due to the addition of excessive Y₂O₃. The spectroscopic characterization of these glasses presented shifts of the infrared and Raman bands, demonstrating the depolymerization of the glass network and the formation of novel P–O–Y bonds, and the deconvoluted Raman spectra also exhibited the occurrence of the disproportionation reaction in the glass melting process. The content of non-bridging oxygen (NBOs) from the UV–vis spectra first increased and then decreased with increasing Y₂O₃. The thermal behaviors show that the Y₂O₃ reduced the crystallization peak temperature and the thermal stability of the glasses. The crystalline behaviors of the phosphate glass matrix were investigated at different crystallization times of 2–10 h, and a transformation of the crystallization mechanism from surface to volume crystallization was found. The yttrium phosphate glass-ceramics crystallized for 10 h exhibited transformation of the main crystalline phases with increasing Y₂O₃, and the grain-oriented crystalline surface became irregular. Full article

(This article belongs to the Section Inorganic Crystalline Materials)

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15 pages, 2203 KiB

Open AccessArticle

Synthesis, Crystal Structure, Hirshfeld Surface Analysis and Docking Studies of a Novel Flavone–Chalcone Hybrid Compound Demonstrating Anticancer Effects by Generating ROS through Glutathione Depletion

by Soon Young Shin, Euitaek Jung, Yoongho Lim, Ha-Jin Lee, Ji Hyun Rhee, Miri Yoo, Seunghyun Ahn and Dongsoo Koh

Crystals 2022, 12(1), 108; https://doi.org/10.3390/cryst12010108 - 14 Jan 2022

Cited by 5 | Viewed by 2106

Abstract

The flavone–chalcone hybrid compound, (E)-6-bromo-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl)-4H-chromen-4-one (3), was synthesized and its three dimensional structure was identified by X-ray crystallography. The compound 3, C₁₉H₁₃BrO₄, was crystallized in the triclinic space group P-1 with the [...] Read more.

The flavone–chalcone hybrid compound, (E)-6-bromo-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl)-4H-chromen-4-one (3), was synthesized and its three dimensional structure was identified by X-ray crystallography. The compound 3, C₁₉H₁₃BrO₄, was crystallized in the triclinic space group P-1 with the following cell parameters: a = 8.2447(6) Å; b = 8.6032(6) Å; c = 11.7826(7) Å; α = 92.456(2)°; β = 91.541(2)°; γ = 106.138(2)°; V = 801.42(9) Å³ and Z = 2. In an asymmetric unit, two molecules are packed by a pi–pi stacking interaction between two flavone rings that are 3.790 Å apart from each other. In the crystal, two hydrogen bonds form inversion dimers and these dimers are extended along the a axis by another hydrogen bond. Hirshfeld analysis revealed that the H–H (34.3%), O–H (19.2%) and C–H (16.7%) intermolecular contacts are the major dominants, while the C–O (6.7%) and C–C (6.5%) are minor dominants. When HCT116 cells were treated with various concentrations of hybrid compound 3, reduced cell viability and induced apoptosis in HCT116 cells were observed in a dose-dependent manner. The treatment of HCT116 colon cancer cells with compound 3, decreased the intracellular glutathione (GSH) levels and generated a reactive oxygen species (ROS). In silico docking experiments between the compound 3 and glutathione S-transferase (GST) containing glutathione were performed to confirm whether the compound 3 binds to glutathione. Their binding energy ranged from −6.6 kcal/mol to −5.0 kcal/mol, and the sulfur of glutathione is very close to the Michael acceptor regions of the compound 3, so it is expected that they would easily react with each other. Compound 3 may be a promising novel anticancer agent by ROS generation through glutathione depletion. Full article

(This article belongs to the Special Issue Feature Papers in Organic Crystalline Materials)

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18 pages, 8115 KiB

Open AccessArticle

Study on the Formation of Reactive Material Shaped Charge Jet by Trans-Scale Discretization Method

by Guancheng Lu, Chao Ge, Zhenyang Liu, Le Tang and Haifu Wang

Crystals 2022, 12(1), 107; https://doi.org/10.3390/cryst12010107 - 14 Jan 2022

Cited by 5 | Viewed by 2085

Abstract

The formation process of reactive materials shaped charge is investigated by X-ray photographs and numerical simulation. In order to study the formation process, a trans-scale discretization method is proposed. A two-dimensional finite element model of shaped charge and reactive material liner is established [...] Read more.

The formation process of reactive materials shaped charge is investigated by X-ray photographs and numerical simulation. In order to study the formation process, a trans-scale discretization method is proposed. A two-dimensional finite element model of shaped charge and reactive material liner is established and the jet formation process, granule size difference induced particle dispersion and granule distribution induced jet particle distribution are analyzed based on Autodyn-2D platform and Euler solver. The result shows that, under shock loading of shaped charge, the Al particle content decreases from the end to the tip of the jet, and increases as the particle size decreases. Besides, the quantity of Al particles at the bottom part of the liner has more prominent influence on the jet head density than that in the other parts, and the Al particle content in the high-speed section of jet shows inversely proportional relationship to the ratio of the particle quantity in the top area to that in the bottom area of liner. Full article

(This article belongs to the Special Issue Dynamic Behavior of Materials)

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14 pages, 3307 KiB

Open AccessReview

Cellulose Nanomaterials as a Future, Sustainable and Renewable Material

by Hoang Thi Phuong, Nguyen Kim Thoa, Phung Thi Anh Tuyet, Quyen Nguyen Van and Yen Dao Hai

Crystals 2022, 12(1), 106; https://doi.org/10.3390/cryst12010106 - 14 Jan 2022

Cited by 22 | Viewed by 4493

Abstract

Cellulose nanomaterials (CNs) are renewable, bio-derived materials that can address not only technological challenges but also social impacts. This ability results from their unique properties, for example, high mechanical strength, high degree of crystallinity, biodegradable, tunable shape, size, and functional surface chemistry. This [...] Read more.

Cellulose nanomaterials (CNs) are renewable, bio-derived materials that can address not only technological challenges but also social impacts. This ability results from their unique properties, for example, high mechanical strength, high degree of crystallinity, biodegradable, tunable shape, size, and functional surface chemistry. This minireview provides chemical and physical features of cellulose nanomaterials and recent developments as an adsorbent and an antimicrobial material generated from bio-renewable sources. Full article

(This article belongs to the Special Issue Confined Crystals, Quantum Dots, and Nano Crystals)

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2 pages, 149 KiB

Open AccessEditorial

Multiscale Modelling and Characterization of Mechanical Properties in Heat-Resistant Alloys

by Ikumu Watanabe, Nobufumi Ueshima, Jovana Ruzic and Hongzhi Cui

Crystals 2022, 12(1), 105; https://doi.org/10.3390/cryst12010105 - 14 Jan 2022

Viewed by 1264

Abstract

Various heat-resistant alloys have been used in industry; however, the bridge between the bulk mechanical properties and the underlying micro- and nanoscopic local properties remains an issue [...] Full article

(This article belongs to the Special Issue Multiscale Modelling and Characterization of Mechanical Properties in Heat-Resistant Alloys)

6 pages, 1129 KiB

Open AccessEditorial

Serial X-ray Crystallography

by Ki Hyun Nam

Crystals 2022, 12(1), 99; https://doi.org/10.3390/cryst12010099 - 13 Jan 2022

Cited by 7 | Viewed by 2865

Abstract

Serial crystallography (SX) is an emerging technique to determine macromolecules at room temperature. SX with a pump–probe experiment provides the time-resolved dynamics of target molecules. SX has developed rapidly over the past decade as a technique that not only provides room-temperature structures with [...] Read more.

Serial crystallography (SX) is an emerging technique to determine macromolecules at room temperature. SX with a pump–probe experiment provides the time-resolved dynamics of target molecules. SX has developed rapidly over the past decade as a technique that not only provides room-temperature structures with biomolecules, but also has the ability to time-resolve their molecular dynamics. The serial femtosecond crystallography (SFX) technique using an X-ray free electron laser (XFEL) has now been extended to serial synchrotron crystallography (SSX) using synchrotron X-rays. The development of a variety of sample delivery techniques and data processing programs is currently accelerating SX research, thereby increasing the research scope. In this editorial, I briefly review some of the experimental techniques that have contributed to advances in the field of SX research and recent major research achievements. This Special Issue will contribute to the field of SX research. Full article

(This article belongs to the Special Issue Serial X-ray Crystallography)

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15 pages, 6255 KiB

Open AccessArticle

Investigation of UV Dye-Sensitized Solar Cells Based on Water Electrolyte: A New Insight for Wavelength-Selective Greenhouse

by Daiana Albulescu, Daniel Ursu, Lucian-Mircea Rusnac, Sabina Nitu, Marinela Miclau and Melinda Vajda

Crystals 2022, 12(1), 98; https://doi.org/10.3390/cryst12010098 - 13 Jan 2022

Cited by 8 | Viewed by 2135

Abstract

The optimization of the photoactive electrode based on TiO₂ with a complex architecture for UV dyes along with water-based electrolyte has successfully allowed us (i) to obtain a photovoltaic efficiency of the dye-sensitized solar cell with 1.45 times higher than the best [...] Read more.

The optimization of the photoactive electrode based on TiO₂ with a complex architecture for UV dyes along with water-based electrolyte has successfully allowed us (i) to obtain a photovoltaic efficiency of the dye-sensitized solar cell with 1.45 times higher than the best efficiency reported for synthetic dye and 3 times for curcumin dye so far; (ii) transparency on the entire Photosynthetic Active Radiation domain; (iii) preserving high efficiency for lighting 1 sun (summer) and shading, especially for 60 mW/cm², which represents the maximum illumination in the rest of the seasons. Our water-based dye-sensitized solar cells loaded with synthetic and natural UV dyes have revealed that the implementation of a dye-sensitized solar cell in autonomous greenhouses is a viable and inexpensive concept. Full article

(This article belongs to the Special Issue Fabrication of Electrodes for Dye-Sensitized Solar Cells)

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6 pages, 4411 KiB

Open AccessEditor’s ChoiceCommunication

Crystallographic Orientation Relationship between α and β Phases during Non-Equilibrium Heat Treatment of Cu-37 wt. % Zn Alloy

by Akbar Heidarzadeh, Mousa Javidani and Lyne St-Georges

Crystals 2022, 12(1), 97; https://doi.org/10.3390/cryst12010097 - 13 Jan 2022

Cited by 1 | Viewed by 2227

Abstract

The crystallographic orientation relationship between α and β phases during the non-equilibrium heat treatment of a Cu-37 wt. % Zn alloy was investigated. With this aim, Cu-37 wt. % Zn alloy plates with a thickness of 2 mm were heated at 810 °C [...] Read more.

The crystallographic orientation relationship between α and β phases during the non-equilibrium heat treatment of a Cu-37 wt. % Zn alloy was investigated. With this aim, Cu-37 wt. % Zn alloy plates with a thickness of 2 mm were heated at 810 °C for 1 h and then were quenched in water. The microstructure and texture of heat-treated samples were analyzed using optical microscopy and electron backscattered diffraction. By this non-equilibrium heat treatment, β phase was formed on both the grain boundaries and grain interiors. In addition, the Σ3 twin boundaries acted as preferred areas for α→β transformation. The orientation imaging microscopy results revealed a Kurdjumov–Sachs (K–S) orientation relationship between α and β phases. Furthermore, the details of microstructural evolution and texture analysis were discussed. Full article

(This article belongs to the Special Issue Microstructure Characterization and Design of Alloys)

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12 pages, 4397 KiB

Open AccessEditor’s ChoiceArticle

Synthesis of Spinel-Hydroxyapatite Composite Utilizing Bovine Bone and Beverage Can

by Agus Pramono, Gerald Ensang Timuda, Ganang Pramudya Ahmad Rifai and Deni Shidqi Khaerudini

Crystals 2022, 12(1), 96; https://doi.org/10.3390/cryst12010096 - 13 Jan 2022

Cited by 4 | Viewed by 2699

Abstract

Spinel-based hydroxyapatite composite (SHC) has been synthesized utilizing bovine bones as the source of the hydroxyapatite (HAp) and beverage cans as the aluminum (Al) source. The bovine bones were defatted and calcined in the air atmosphere to transform them into hydroxyapatite. The beverage [...] Read more.

Spinel-based hydroxyapatite composite (SHC) has been synthesized utilizing bovine bones as the source of the hydroxyapatite (HAp) and beverage cans as the aluminum (Al) source. The bovine bones were defatted and calcined in the air atmosphere to transform them into hydroxyapatite. The beverage cans were cut and milled to obtain fine Al powder and then sieved to obtain three different particle mesh size fractions: +100#, −140# + 170#, and −170#, or Al particle size of >150, 90–150, and <90 µm, respectively. The SHC was synthesized using the self-propagating intermediate-temperature synthesis (SIS) method at 900 °C for 2 h with (HAp:Al:Mg) ratio of (87:10:3 wt.%) and various compaction pressure of 100, 171, and 200 MPa. It was found that the mechanical properties of the SHC are influenced by the Al particle size and the compaction pressure. Smaller particle size produces the tendency of increasing the hardness and reducing the porosity of the composite. Meanwhile, increasing compaction pressure produces a reduction of the SHC porosity. The increase in the hardness is also observed by increasing the compaction pressure except for the smallest Al particle size (<90 µm), where the hardness instead becomes smaller. Full article

(This article belongs to the Special Issue Mineralogical Crystallography (2nd Edition))

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16 pages, 3521 KiB

Open AccessArticle

Correlations between Garnet Species and Vibration Spectroscopy: Isomorphous Substitution Implications

by Weiwei Li, Jinyu Zheng, Jingcheng Pei, Xing Xu and Tao Chen

Crystals 2022, 12(1), 104; https://doi.org/10.3390/cryst12010104 - 13 Jan 2022

Cited by 7 | Viewed by 5693

Abstract

Garnet has many species because of its common isomorphism. In this study, a suite of 25 natural gem-quality garnets, including pyrope, almandine, spessartine, grossular, and andradite, were examined by standard gemological testing, LA-ICP-MS, FTIR, and Raman analysis. Internal stretching and bending vibrations of [...] Read more.

Garnet has many species because of its common isomorphism. In this study, a suite of 25 natural gem-quality garnets, including pyrope, almandine, spessartine, grossular, and andradite, were examined by standard gemological testing, LA-ICP-MS, FTIR, and Raman analysis. Internal stretching and bending vibrations of the SiO₄-tetrahedra of garnet exhibit correlate with the type of cations in garnet’s dodecahedral position (A site) and octahedral position (B site). FTIR and Raman spectra showed that with the increase of the radius of Mg²⁺, Fe²⁺, Mn²⁺, and Ca²⁺ in A site, or the unit cell volumes of pyrope, almandine, spessartine, and grossular, the spectral peaks of Si–O_str and Si–O_bend modes shift to low wavenumber. Because of the largest cations both in A site (Ca²⁺) and in B site (Fe³⁺), andradite exhibited the lowest wavenumber of Si–O_str and Si–O_bend modes of the five garnet species. Therefore, garnet has correlations between chemical composition and vibration spectroscopy, and Raman or IR spectroscopy can be used to precisely identify garnet species. Full article

(This article belongs to the Special Issue Gem Crystals)

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12 pages, 2316 KiB

Open AccessEditor’s ChoiceArticle

Processing of Multicrystal Diffraction Patterns in Macromolecular Crystallography Using Serial Crystallography Programs

by Ki Hyun Nam

Crystals 2022, 12(1), 103; https://doi.org/10.3390/cryst12010103 - 13 Jan 2022

Cited by 7 | Viewed by 3072

Abstract

Cryocrystallography is a widely used method for determining the crystal structure of macromolecules. This technique uses a cryoenvironment, which significantly reduces the radiation damage to the crystals and has the advantage of requiring only one crystal for structural determination. In standard cryocrystallography, a [...] Read more.

Cryocrystallography is a widely used method for determining the crystal structure of macromolecules. This technique uses a cryoenvironment, which significantly reduces the radiation damage to the crystals and has the advantage of requiring only one crystal for structural determination. In standard cryocrystallography, a single crystal is used for collecting diffraction data, which include single-crystal diffraction patterns. However, the X-ray data recorded often may contain diffraction patterns from several crystals. The indexing of multicrystal diffraction patterns in cryocrystallography requires more precise data processing techniques and is therefore time consuming. Here, an approach for processing multicrystal diffraction data using a serial crystallography program is introduced that allows for the integration of multicrystal diffraction patterns from a single image. Multicrystal diffraction data were collected from lysozyme crystals and processed using the serial crystallography program CrystFEL. From 360 images containing multicrystal diffraction patterns, 1138 and 691 crystal lattices could be obtained using the XGANDALF and MOSFLM indexing algorithms, respectively. Using this indexed multi-lattice information, the crystal structure of the lysozyme could be determined successfully at a resolution of 1.9 Å. Therefore, the proposed approach, which is based on serial crystallography, is suitable for processing multicrystal diffraction data in cryocrystallography. Full article

(This article belongs to the Special Issue Serial X-ray Crystallography)

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8 pages, 2018 KiB

Open AccessArticle

A Discrepancy in Thermal Conductivity Measurement Data of Quantum Spin Liquid β′-EtMe₃Sb[Pd(dmit)₂]₂ (dmit = 1,3-Dithiol-2-thione-4,5-dithiolate)

by Reizo Kato, Masashi Uebe, Shigeki Fujiyama and Hengbo Cui

Crystals 2022, 12(1), 102; https://doi.org/10.3390/cryst12010102 - 13 Jan 2022

Cited by 12 | Viewed by 3295

Abstract

A molecular Mott insulator β′-EtMe₃Sb[Pd(dmit)₂]₂ is a quantum spin liquid candidate. In 2010, it was reported that thermal conductivity of β′-EtMe₃Sb[Pd(dmit)₂]₂ is characterized by its large value and gapless behavior (a finite temperature-linear [...] Read more.

A molecular Mott insulator β′-EtMe₃Sb[Pd(dmit)₂]₂ is a quantum spin liquid candidate. In 2010, it was reported that thermal conductivity of β′-EtMe₃Sb[Pd(dmit)₂]₂ is characterized by its large value and gapless behavior (a finite temperature-linear term). In 2019, however, two other research groups reported opposite data (much smaller value and a vanishingly small temperature-linear term) and the discrepancy in the thermal conductivity measurement data emerges as a serious problem concerning the ground state of the quantum spin liquid. Recently, the cooling rate was proposed to be an origin of the discrepancy. We examined effects of the cooling rate on electrical resistivity, low-temperature crystal structure, and ¹³C-NMR measurements and could not find any significant cooling rate dependence. Full article

(This article belongs to the Special Issue New Spin on Metal-Insulator Transitions)

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31 pages, 13217 KiB

Open AccessReview

A Review on Precision Polishing Technology of Single-Crystal SiC

by Gaoling Ma, Shujuan Li, Feilong Liu, Chen Zhang, Zhen Jia and Xincheng Yin

Crystals 2022, 12(1), 101; https://doi.org/10.3390/cryst12010101 - 13 Jan 2022

Cited by 32 | Viewed by 9067

Abstract

Single-crystal SiC is a typical third-generation semiconductor power-device material because of its excellent electronic and thermal properties. An ultrasmooth surface with atomic surface roughness that is scratch free and subsurface damage (SSD) free is indispensable before its application. As the last process to [...] Read more.

Single-crystal SiC is a typical third-generation semiconductor power-device material because of its excellent electronic and thermal properties. An ultrasmooth surface with atomic surface roughness that is scratch free and subsurface damage (SSD) free is indispensable before its application. As the last process to reduce the surface roughness and remove surface defects, precision polishing of single-crystal SiC is essential. In this paper, precision polishing technologies for 4H-SiC and 6H-SiC, which are the most commonly used polytypes of single-crystal SiC, such as chemical mechanical polishing (CMP), photocatalytic chemical mechanical polishing (PCMP), plasma-assisted polishing (PAP), electrochemical mechanical polishing (ECMP), and catalyst-referred etching (CARE), were reviewed and compared with emphasis on the experimental setup, polishing mechanism, material removal rate (MRR), and surface roughness. An atomically smooth surface without SSD can be obtained by CMP, PCMP, PAP, and CARE for single-crystal SiC. However, their MRRs are meager, and the waste treatment after CMP is difficult and expensive. Moreover, PAP’s operation is poor due to the complex polishing system, plasma generation, and irradiation devices. A high MRR can be achieved by ECMP. In addition, it is an environmentally friendly precision polishing process for single-crystal SiC since the neutral salt solution is generally used as the electrolyte in ECMP. However, the formation of the egglike protrusions at the oxide/SiC interface during anodic oxidation would lead to a bigger surface roughness after ECMP than that after PAP is processed. The HF solution used in CARE was toxic, and Pt was particularly expensive. Ultrasonic vibration-assisted single-crystal SiC polishing and electrolyte plasma polishing (EPP) were discussed; furthermore, the research direction of further improving the surface quality and MRR of single-crystal SiC was prospected. Full article

(This article belongs to the Special Issue Advanced Semiconductor Materials and Devices)

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14 pages, 6346 KiB

Open AccessEditor’s ChoiceArticle

Numerical Investigation into the Influence of Grain Orientation Distribution on the Local and Global Elastic-Plastic Behaviour of Polycrystalline Nickel-Based Superalloy INC-738 LC

by Benedikt Engel, Mark Huth and Christopher Hyde

Crystals 2022, 12(1), 100; https://doi.org/10.3390/cryst12010100 - 13 Jan 2022

Cited by 6 | Viewed by 2695

Abstract

Polycrystalline nickel-based superalloys tend to have large grains within component areas where high loads are dominant during operation. Due to these large grains, caused by the manufacturing and cooling process, the orientation of each grain becomes highly important, since it influences the elastic [...] Read more.

Polycrystalline nickel-based superalloys tend to have large grains within component areas where high loads are dominant during operation. Due to these large grains, caused by the manufacturing and cooling process, the orientation of each grain becomes highly important, since it influences the elastic and plastic behaviour of the material. With the usage of the open source codes NEPER and FEPX, polycrystalline models of Inconel 738 LC were generated and their elastic and crystal plasticity behaviour simulated in dependence of different orientation distributions under uniaxial loading. Orientation distributions close to the [100] direction showed the lowest Young’s moduli as well as the highest elastic strains before yielding, as expected. Orientations close to the [

\bar{5}

89] direction, showed the lowest elastic strains and therefore first plastic deformation under strain loading due to the highest shear stress in the slip systems caused by the interaction of Young’s modulus and the Schmid factor. Full article

(This article belongs to the Special Issue Crystal Plasticity (Volume II))

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15 pages, 3599 KiB

Open AccessArticle

Synthesis, Crystal Structures and Magnetic Properties of Trinuclear {Ni₂Ln} (Ln^III = Dy, Ho) and {Ni₂Y} Complexes with Schiff Base Ligands

by Despina Dermitzaki, Angeliki Panagiotopoulou, Michael Pissas, Yiannis Sanakis, Vassilis Psycharis and Catherine P. Raptopoulou

Crystals 2022, 12(1), 95; https://doi.org/10.3390/cryst12010095 - 11 Jan 2022

Cited by 5 | Viewed by 2015

Abstract

The reaction of the Schiff base ligand o-OH-C₆H₄-CH=N-C(CH₂OH)₃, H₄L, with Ni(O₂CMe)₂∙4H₂O and lanthanide nitrate salts in a 4:2:1 ratio lead to the formation of the trinuclear complexes [...] Read more.

The reaction of the Schiff base ligand o-OH-C₆H₄-CH=N-C(CH₂OH)₃, H₄L, with Ni(O₂CMe)₂∙4H₂O and lanthanide nitrate salts in a 4:2:1 ratio lead to the formation of the trinuclear complexes [Ni₂Ln(H₃L)₄(O₂CMe)₂](NO₃) (Ln = Dy (1), Ho (2), and Y (3)) which crystallize in the non-centrosymmetric space group Pna2₁. The complex cation consists of the three metal ions in an almost linear arrangement. The {Ni₂Ln} moieties are bridged through two deprotonated O_phenolato groups from two different ligands. Each terminal Ni^II ion is bound to two ligands through their O_phenolato, the N_imino atoms and one of the protonated O_alkoxo groups in a distorted octahedral. The central lanthanide ion is coordinated to four O_phenolato oxygen from the four ligands, and four O_carboxylato atoms from two acetates which are bound in the bidentate chelate mode, and the coordination polyhedron is biaugmented trigonal prism, which probably results in a non-centrosymmetric arrangement of the complexes in the lattice. The magnetic properties of 1–3 were studied and showed that 1 exhibits field induced slow magnetic relaxation. Full article

(This article belongs to the Special Issue Synthesis and Characterization of Molecular Magnetic Materials Based on Coordination Chemistry)

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17 pages, 4993 KiB

Open AccessEditor’s ChoiceReview

Recent Progresses on Experimental Investigations of Topological and Dissipative Solitons in Liquid Crystals

by Yuan Shen and Ingo Dierking

Crystals 2022, 12(1), 94; https://doi.org/10.3390/cryst12010094 - 11 Jan 2022

Cited by 14 | Viewed by 3330

Abstract

Solitons in liquid crystals have received increasing attention due to their importance in fundamental physical science and potential applications in various fields. The study of solitons in liquid crystals has been carried out for over five decades with various kinds of solitons being [...] Read more.

Solitons in liquid crystals have received increasing attention due to their importance in fundamental physical science and potential applications in various fields. The study of solitons in liquid crystals has been carried out for over five decades with various kinds of solitons being reported. Recently, a number of new types of solitons have been observed, among which, many of them exhibit intriguing dynamic behaviors. In this paper, we briefly review the recent progresses on experimental investigations of solitons in liquid crystals. Full article

(This article belongs to the Special Issue State-of-the-Art Liquid Crystals Research in UK)

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